I was curious if it might be possible to make the 30-06 work in the AR-10 platform. I know they are slightly longer, but still kinda fit in the mag. This is just a brain storm idea and was curious what you guys thought.
- Thread starter demonsmokr
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Re: 30-06 AR?
They won't "kind of" fit in the mag. '06 is 1/2" longer than .308 and you would need a new magazine/lower receiver design. I think there was a company that made one at one time but it never took off. Cobb maybe? Think Bushmaster ended up owning it, haven't heard anything about it in a long time.
They won't "kind of" fit in the mag. '06 is 1/2" longer than .308 and you would need a new magazine/lower receiver design. I think there was a company that made one at one time but it never took off. Cobb maybe? Think Bushmaster ended up owning it, haven't heard anything about it in a long time.
Re: 30-06 AR?
COBB made one but I don't know that it is still in production, because like Falar said, bushy bought them up (and in turn got sucked up by cerebus). You might find one on gunbroker if you look from time to time.
RND doesn't show one on their site, but if you are willing to fork out a little extra they might make you one on the longer lapua action but with the correct bolt for .30-06 (.473" face).
Really isn't much out there for what you want, it's not ever gonna fit in a regular .308 AR action. If I might offer my 2 cents... this is a stupid thing to spend a lot of money on to gain a mediocre ballistic advantage over a regular .308 win rifle. '06 does have a little bit more case capacity, but the gains are so small that it really doesn't justify a custom setup like this IMHO.
COBB made one but I don't know that it is still in production, because like Falar said, bushy bought them up (and in turn got sucked up by cerebus). You might find one on gunbroker if you look from time to time.
RND doesn't show one on their site, but if you are willing to fork out a little extra they might make you one on the longer lapua action but with the correct bolt for .30-06 (.473" face).
Really isn't much out there for what you want, it's not ever gonna fit in a regular .308 AR action. If I might offer my 2 cents... this is a stupid thing to spend a lot of money on to gain a mediocre ballistic advantage over a regular .308 win rifle. '06 does have a little bit more case capacity, but the gains are so small that it really doesn't justify a custom setup like this IMHO.
Re: 30-06 AR?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bcw1284</div><div class="ubbcode-body">COBB made one but I don't know that it is still in production, because like Falar said, bushy bought them up (and in turn got sucked up by cerebus). You might find one on gunbroker if you look from time to time.
RND doesn't show one on their site, but if you are willing to fork out a little extra they might make you one on the longer lapua action but with the correct bolt for .30-06 (.473" face).
Really isn't much out there for what you want, it's not ever gonna fit in a regular .308 AR action. If I might offer my 2 cents... this is a stupid thing to spend a lot of money on to gain a mediocre ballistic advantage over a regular .308 win rifle. '06 does have a little bit more case capacity, but the gains are so small that it really doesn't justify a custom setup like this IMHO. </div></div>
And the case capacity advantage is severely limited by the fact that the 06 runs a lower PSI. Which is why a round 1/2" longer can only manage a 100fps or so faster at best
Unless the OP has some need for 180gr+ bullets, there is no reason to go with 30.06; especially with the kind of additional cost we're talking here. If you need a full-power .30 AR, Buy one in .308 and be done with it.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bcw1284</div><div class="ubbcode-body">COBB made one but I don't know that it is still in production, because like Falar said, bushy bought them up (and in turn got sucked up by cerebus). You might find one on gunbroker if you look from time to time.
RND doesn't show one on their site, but if you are willing to fork out a little extra they might make you one on the longer lapua action but with the correct bolt for .30-06 (.473" face).
Really isn't much out there for what you want, it's not ever gonna fit in a regular .308 AR action. If I might offer my 2 cents... this is a stupid thing to spend a lot of money on to gain a mediocre ballistic advantage over a regular .308 win rifle. '06 does have a little bit more case capacity, but the gains are so small that it really doesn't justify a custom setup like this IMHO. </div></div>
And the case capacity advantage is severely limited by the fact that the 06 runs a lower PSI. Which is why a round 1/2" longer can only manage a 100fps or so faster at best
Unless the OP has some need for 180gr+ bullets, there is no reason to go with 30.06; especially with the kind of additional cost we're talking here. If you need a full-power .30 AR, Buy one in .308 and be done with it.
Re: 30-06 AR?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DP425</div><div class="ubbcode-body">
And the case capacity advantage is severely limited by the fact that the 06 runs a lower PSI. Which is why a round 1/2" longer can only manage a 100fps or so faster at best
</div></div>
You may want to do a little more investigating about your theory here.
The pressure that a 30-06 operates at is limited by the case head design, that same design is used in the 308. It is the Mauser case head from circa 1896 and it's good for about 65ksi without brass growth issues.
The reason that books show lower pressures is because of the early 30-06 rifles out there and rare Springfield that might not be able to take the pressure. With modern actions and steels the 30-06 is head and shoulders above the 308 with the same pressure and 30% more case capacity.
Secondly, 100fps faster is wrong. Here's actual chrono data from identical bullets shot from identical barrels that were simply chambered in 308 vs. 30-06
26" Finished length 1:10tw 4 groove SS Match barrels
<span style="font-weight: bold">150 FMJ's</span>
308 - 2925 fps
30-06 - 3175fps
difference: 250fps
<span style="font-weight: bold">168 Amax</span>
308 - 2765fps
30-06 - 3045fps
<span style="font-weight: bold">178 Amax</span>
308 - 2685
30-06 - 2985
<span style="font-weight: bold">208 Amax</span>
308 - 2550
30-06 - 2875
Now, those numbers are shot through bolt rifles with longer than normal barrels when compared to a gas gun. For a gas gun it's difficult to run the same powders and therefore, same speeds as those loads but it can be done with a tuned gas block.
The problem is going to be finding a platform that can handle a 3.4" long round loaded from the magazine in a semi-auto. If RND can do it I think that they'd have a pretty solid rifle. I think that they have done 300WM rounds in their 338Lap platform and that's a similar step up from the 30-06 too.
The key is loading properly and not believing campfire stories about the 308 being better than the 30-06.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DP425</div><div class="ubbcode-body">
And the case capacity advantage is severely limited by the fact that the 06 runs a lower PSI. Which is why a round 1/2" longer can only manage a 100fps or so faster at best
</div></div>
You may want to do a little more investigating about your theory here.
The pressure that a 30-06 operates at is limited by the case head design, that same design is used in the 308. It is the Mauser case head from circa 1896 and it's good for about 65ksi without brass growth issues.
The reason that books show lower pressures is because of the early 30-06 rifles out there and rare Springfield that might not be able to take the pressure. With modern actions and steels the 30-06 is head and shoulders above the 308 with the same pressure and 30% more case capacity.
Secondly, 100fps faster is wrong. Here's actual chrono data from identical bullets shot from identical barrels that were simply chambered in 308 vs. 30-06
26" Finished length 1:10tw 4 groove SS Match barrels
<span style="font-weight: bold">150 FMJ's</span>
308 - 2925 fps
30-06 - 3175fps
difference: 250fps
<span style="font-weight: bold">168 Amax</span>
308 - 2765fps
30-06 - 3045fps
<span style="font-weight: bold">178 Amax</span>
308 - 2685
30-06 - 2985
<span style="font-weight: bold">208 Amax</span>
308 - 2550
30-06 - 2875
Now, those numbers are shot through bolt rifles with longer than normal barrels when compared to a gas gun. For a gas gun it's difficult to run the same powders and therefore, same speeds as those loads but it can be done with a tuned gas block.
The problem is going to be finding a platform that can handle a 3.4" long round loaded from the magazine in a semi-auto. If RND can do it I think that they'd have a pretty solid rifle. I think that they have done 300WM rounds in their 338Lap platform and that's a similar step up from the 30-06 too.
The key is loading properly and not believing campfire stories about the 308 being better than the 30-06.
Re: 30-06 AR?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bohem</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DP425</div><div class="ubbcode-body">
And the case capacity advantage is severely limited by the fact that the 06 runs a lower PSI. Which is why a round 1/2" longer can only manage a 100fps or so faster at best
</div></div>
You may want to do a little more investigating about your theory here.
The key is loading properly and not believing campfire stories about the 308 being better than the 30-06. </div></div>
The problem seems to be so many people using the same powders with med burn rates in the two cartridges since the original '06 powders (like 4895) fell in that range. "It is what the cartridge was designed for" "it has worked for 100 years" usually being the mantra. They work, and can work well especially with light bullets but over the years advancements have been made in slower burning powders that more efficiently use the '06 case (especially with heavy bullets) but like you said, this data isn't out there because of the "old gun factor".
Then you see gems like this that just make you shake your head:
http://www.snipercountry.com/Articles/AccuracyFacts.asp
".30-06 is dead, .308 is more accurate and is available in a short action and is only 100fps slower"
I've seen this myth posted repeatedly all over the net on several forums.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bohem</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DP425</div><div class="ubbcode-body">
And the case capacity advantage is severely limited by the fact that the 06 runs a lower PSI. Which is why a round 1/2" longer can only manage a 100fps or so faster at best
</div></div>
You may want to do a little more investigating about your theory here.
The key is loading properly and not believing campfire stories about the 308 being better than the 30-06. </div></div>
The problem seems to be so many people using the same powders with med burn rates in the two cartridges since the original '06 powders (like 4895) fell in that range. "It is what the cartridge was designed for" "it has worked for 100 years" usually being the mantra. They work, and can work well especially with light bullets but over the years advancements have been made in slower burning powders that more efficiently use the '06 case (especially with heavy bullets) but like you said, this data isn't out there because of the "old gun factor".
Then you see gems like this that just make you shake your head:
http://www.snipercountry.com/Articles/AccuracyFacts.asp
".30-06 is dead, .308 is more accurate and is available in a short action and is only 100fps slower"
I've seen this myth posted repeatedly all over the net on several forums.
Re: 30-06 AR?
Interesting.... since the listed max PSI is about 60,200 for .308 and 58,700 for 30.60. Of course, what you're saying is, because .30-06 is old, the max pressure can be adjusted up to more modern caliber's so long as it is with modern firearms. That's an interesting theory.
Also, I believe it would be more wise to compare load data, not someone's concoction that no one knows if the pressure it is producing is within spec or not.
Hodgdon says, straight from their data book:
130gr speer HP:
Max for .30-06: 3243
Max for .308: 3153
Difference: 110fps
155gr SMK:
Max for .30-06: 3038
Max for .308: 2909
Difference: 129fps
175gr SMK
Max for .30-06: 2842
Max for .308: 2728
Difference: 114fps
190gr Hornady BTSP
Max for .30-06: 2692
Max for .308: 2571
Difference: 121 fps
And this is pretty much what you see with all load data- a variation of 90-160 fps. Now if you want to say fuck the pressure limits and stuff that 06 case- be my guest... but if you're looking to run loads within spec, the difference between 06 and .308 is negligible unless it is your desire to run 190-250gr projectiles. All of that case capacity is wasted with modern powders- UNLESS you're ignoring pressure specs. The key design goals of the .308 were 1.) closely match ballistics of .30-06. 2.) Make use of modern powders requiring less volume. 3.) decrease over-all length of the round. They did a pretty good job of meeting all goals
No one said the .308 is BETTER than the .30-06.... just that it is virtually identical up to it's limitations on bullet weight.
I will again say, 100-150fps is not worth the extra money you'll spend.
Edit: The data above is not using the same powder for each caliber- that is the best load for velocity listed. So that should remove the argument of using the right powder.
Interesting.... since the listed max PSI is about 60,200 for .308 and 58,700 for 30.60. Of course, what you're saying is, because .30-06 is old, the max pressure can be adjusted up to more modern caliber's so long as it is with modern firearms. That's an interesting theory.
Also, I believe it would be more wise to compare load data, not someone's concoction that no one knows if the pressure it is producing is within spec or not.
Hodgdon says, straight from their data book:
130gr speer HP:
Max for .30-06: 3243
Max for .308: 3153
Difference: 110fps
155gr SMK:
Max for .30-06: 3038
Max for .308: 2909
Difference: 129fps
175gr SMK
Max for .30-06: 2842
Max for .308: 2728
Difference: 114fps
190gr Hornady BTSP
Max for .30-06: 2692
Max for .308: 2571
Difference: 121 fps
And this is pretty much what you see with all load data- a variation of 90-160 fps. Now if you want to say fuck the pressure limits and stuff that 06 case- be my guest... but if you're looking to run loads within spec, the difference between 06 and .308 is negligible unless it is your desire to run 190-250gr projectiles. All of that case capacity is wasted with modern powders- UNLESS you're ignoring pressure specs. The key design goals of the .308 were 1.) closely match ballistics of .30-06. 2.) Make use of modern powders requiring less volume. 3.) decrease over-all length of the round. They did a pretty good job of meeting all goals
No one said the .308 is BETTER than the .30-06.... just that it is virtually identical up to it's limitations on bullet weight.
I will again say, 100-150fps is not worth the extra money you'll spend.
Edit: The data above is not using the same powder for each caliber- that is the best load for velocity listed. So that should remove the argument of using the right powder.
Re: 30-06 AR?
This issue is argued here all the time and the people who have actually spent the time/money/sweat to put the myth to bed clearly have demonstrated the behavior between the two rounds.
Here's something else to consider:
Look at the max listed pressures for 22-250, 243, 260, 7mm-08, 270, 280, 30-06 and see what kind of max pressure variance you find.
The case head is identical in all of these cases. That's the governing factor, if it's identical you can push the same peak pressures from all of them.
This issue is argued here all the time and the people who have actually spent the time/money/sweat to put the myth to bed clearly have demonstrated the behavior between the two rounds.
Here's something else to consider:
Look at the max listed pressures for 22-250, 243, 260, 7mm-08, 270, 280, 30-06 and see what kind of max pressure variance you find.
The case head is identical in all of these cases. That's the governing factor, if it's identical you can push the same peak pressures from all of them.
Re: 30-06 AR?
wow, i've created a monster. I should have known that a case comparison would turn this into an epic thread.
Personally, I use the '06 in my bolt guns... but the cost to do it in a gas gun would be a dumb investment IMHO. If you want increased ballistic performance from that platform, there are several out there in SAUM or WSM (including those from RND).
I will just save my pennies and buy a Noreen in lapua if I really feel the need for a gas gun that has insane long range ballistics.
wow, i've created a monster. I should have known that a case comparison would turn this into an epic thread.
Personally, I use the '06 in my bolt guns... but the cost to do it in a gas gun would be a dumb investment IMHO. If you want increased ballistic performance from that platform, there are several out there in SAUM or WSM (including those from RND).
I will just save my pennies and buy a Noreen in lapua if I really feel the need for a gas gun that has insane long range ballistics.
Re: 30-06 AR?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bohem</div><div class="ubbcode-body">This issue is argued here all the time and the people who have actually spent the time/money/sweat to put the myth to bed clearly have demonstrated the behavior between the two rounds.
Here's something else to consider:
Look at the max listed pressures for 22-250, 243, 260, 7mm-08, 270, 280, 30-06 and see what kind of max pressure variance you find.
The case head is identical in all of these cases. That's the governing factor, if it's identical you can push the same peak pressures from all of them.
</div></div>
Then why don't they have the same pressure spec? Right now you are arguing that it's perfectly safe to bump up a lower SPECIFIED chamber pressure so long as the case head is of the same design. Lets take .38 SPC, .38 SPC+P and .357Mag...
SPC: 17,000
+P: 18,500
Mag: 35,000
They share the same design case head- there for you should be able to push a .38 special loading up to 35,000 PSI. I'm not totally sure- I'm not an engineer or anything, but I was under the impression that case pressure is distributed throughout all bearing metal surrounding the case. Just because a cartridge is designed off of another does not mean it is designed to run the same pressure.
That idea is totally ignorant. Keep your pressures as advertised. No one is disputing that the .30-06 will send a bullet faster, or that it has the capability to chamber heavier (read:longer) bullets. But in-spec loadings do not produce a worthwhile velocity difference within the range of bullets that can be loaded to .308.
If there were no such thing as SAAMI specs, I would be agreeing with you all day long. And I'll even agree with you, that if you hold the .308 to it's pressure specs, but ignore the specs for the .30-06, you'll have note-worthy velocity increase over .308. But staying within SAAMI specs, .30-06's only real advantage is in the ability to throw longer bullets. I'm not saying either is inherently more accurate than the other, but 100-150fps is really nothing to get excited about.
Finally, to the OP- there are MUCH better options available that will not cost you a great deal more for not so much gain. If it were a bolt gun and you wanted to go .30-06 I wouldn't even have posted on here- price difference between a short action and medium/long action rifle otherwise the same is really negligible. So in that respect go with whatever your interested in. But when we're talking about an AR, which would be very rare and unconventional... driving costs up considerably... There are better ways to go (such as some of those short mag's listed above).
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bohem</div><div class="ubbcode-body">This issue is argued here all the time and the people who have actually spent the time/money/sweat to put the myth to bed clearly have demonstrated the behavior between the two rounds.
Here's something else to consider:
Look at the max listed pressures for 22-250, 243, 260, 7mm-08, 270, 280, 30-06 and see what kind of max pressure variance you find.
The case head is identical in all of these cases. That's the governing factor, if it's identical you can push the same peak pressures from all of them.
</div></div>
Then why don't they have the same pressure spec? Right now you are arguing that it's perfectly safe to bump up a lower SPECIFIED chamber pressure so long as the case head is of the same design. Lets take .38 SPC, .38 SPC+P and .357Mag...
SPC: 17,000
+P: 18,500
Mag: 35,000
They share the same design case head- there for you should be able to push a .38 special loading up to 35,000 PSI. I'm not totally sure- I'm not an engineer or anything, but I was under the impression that case pressure is distributed throughout all bearing metal surrounding the case. Just because a cartridge is designed off of another does not mean it is designed to run the same pressure.
That idea is totally ignorant. Keep your pressures as advertised. No one is disputing that the .30-06 will send a bullet faster, or that it has the capability to chamber heavier (read:longer) bullets. But in-spec loadings do not produce a worthwhile velocity difference within the range of bullets that can be loaded to .308.
If there were no such thing as SAAMI specs, I would be agreeing with you all day long. And I'll even agree with you, that if you hold the .308 to it's pressure specs, but ignore the specs for the .30-06, you'll have note-worthy velocity increase over .308. But staying within SAAMI specs, .30-06's only real advantage is in the ability to throw longer bullets. I'm not saying either is inherently more accurate than the other, but 100-150fps is really nothing to get excited about.
Finally, to the OP- there are MUCH better options available that will not cost you a great deal more for not so much gain. If it were a bolt gun and you wanted to go .30-06 I wouldn't even have posted on here- price difference between a short action and medium/long action rifle otherwise the same is really negligible. So in that respect go with whatever your interested in. But when we're talking about an AR, which would be very rare and unconventional... driving costs up considerably... There are better ways to go (such as some of those short mag's listed above).
Re: 30-06 AR?
I thought you might be able to get shorter bullets. But 1/2 is way too much. I was just brain storming all day yesterday while my internet was out and got to looking at the rounds. The case will fit in the mag, but the bullet is too long. The difference is mediocre at best from the 2 rounds. I was not wanting to modify my gun to this caliber, I was just curious and wanted to satisfy my brains itch, I have seen the other calibers which all use the same 308 type case. Isnt the 7.62x54R related to the 30-06? Or is it solely a russian engineered round?
I thought you might be able to get shorter bullets. But 1/2 is way too much. I was just brain storming all day yesterday while my internet was out and got to looking at the rounds. The case will fit in the mag, but the bullet is too long. The difference is mediocre at best from the 2 rounds. I was not wanting to modify my gun to this caliber, I was just curious and wanted to satisfy my brains itch, I have seen the other calibers which all use the same 308 type case. Isnt the 7.62x54R related to the 30-06? Or is it solely a russian engineered round?
Re: 30-06 AR?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DP425</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bohem</div><div class="ubbcode-body">This issue is argued here all the time and the people who have actually spent the time/money/sweat to put the myth to bed clearly have demonstrated the behavior between the two rounds.
Here's something else to consider:
Look at the max listed pressures for 22-250, 243, 260, 7mm-08, 270, 280, 30-06 and see what kind of max pressure variance you find.
The case head is identical in all of these cases. That's the governing factor, if it's identical you can push the same peak pressures from all of them.
</div></div>
Then why don't they have the same pressure spec? Right now you are arguing that it's perfectly safe to bump up a lower SPECIFIED chamber pressure so long as the case head is of the same design. Lets take .38 SPC, .38 SPC+P and .357Mag...
SPC: 17,000
+P: 18,500
Mag: 35,000
They share the same design case head- there for you should be able to push a .38 special loading up to 35,000 PSI. I'm not totally sure- <span style="font-weight: bold">I'm not an engineer or anything</span>, but I was under the impression that case pressure is distributed throughout all bearing metal surrounding the case. Just because a cartridge is designed off of another does not mean it is designed to run the same pressure. <span style="font-weight: bold">This where your "understanding" is incomplete</span>
That idea is totally ignorant. Keep your pressures as advertised. No one is disputing that the .30-06 will send a bullet faster, or that it has the capability to chamber heavier (read:longer) bullets. But in-spec loadings do not produce a worthwhile velocity difference within the range of bullets that can be loaded to .308.
If there were no such thing as SAAMI specs, I would be agreeing with you all day long. And I'll even agree with you, that if you hold the .308 to it's pressure specs, but ignore the specs for the .30-06, you'll have note-worthy velocity increase over .308. But staying within SAAMI specs, .30-06's only real advantage is in the ability to throw longer bullets. I'm not saying either is inherently more accurate than the other, but 100-150fps is really nothing to get excited about.
Finally, to the OP- there are MUCH better options available that will not cost you a great deal more for not so much gain. If it were a bolt gun and you wanted to go .30-06 I wouldn't even have posted on here- price difference between a short action and medium/long action rifle otherwise the same is really negligible. So in that respect go with whatever your interested in. But when we're talking about an AR, which would be very rare and unconventional... driving costs up considerably... There are better ways to go (such as some of those short mag's listed above). </div></div>
So you're not an engineer but you're going to give me, the mechanical engineer who's actually modeled time dependent (aka transient state) internal models of the stresses involved in an action, a lesson on how the load paths and yield criteria in a rifle action a developed?
The 38/38+P/357 example you posted is written in total ignorance, if you knew the history of how the 357 and the 44mag were developed you'd already know where those pressure ratings come from.
Here's a short history:
38 shooters decided that more could be gleaned from the modern steels in the big revolvers being produced after WWI. The leaps in military rifles and steels leading up to WWI and thereafter meant that (then) recently produced revolvers with strong top straps and higher strength parts could take more abuse. The initial developments were done on retro-fit pistols meant for the bigger revolver rounds that had been refitted with 38 Spc barrels and chambers.
So, the key contributors to that round started pushing more and more powder into the 38 Spc. cases and seeing how hard things could be pushed.
Clearly this ammo was not meant for the vast majority of the 38's on the market so a geometry change to the cases had to be made so that they could not be mistakenly fired in a "weak" 38. This is why the case was lengthened so that it would not fit in a standard 38 Spc.
The +P is a new designation that was deemed feasible when the magnum handgun craze was sweeping the industry to sell more 38 Spc. ammo. It could be safely shot in the 38's and it simply reduced the safety factor, but the safety factors being set high in this industry the reduction was deemed feasible. Note that the difference between a 38 and 38+P is 1500psi or less than a 10% increase.
357's are literally double the pressure and it's clear why that would not be safe, but also note that the case head didn't change, it was the actual firearm that was limiting the chambering and not the ammunition design.
So, now back to the 30-06 vs. 308 debate. The pressure specs by SAAMI are simply listed and organized by SAAMI. The body does not regulate what a company does when branding or submitting the ammunition for spec publication.
The 22-250 is a Remington "invention" (or appropriately an adoption) while the 308 is an adoption by Winchester. This entitles the respective companies to tie "Remington" or "Winchester" to the name. We don't call the 22-250 the 22-250/300 Savage which is its true lineage, it's named by the company who adopted it and submitted to SAAMI for the spec publication.
So, now, going back to the way pressure is distributed in the case:
Yes, the wetted surfaces inside the case would all see a constant pressure reading in "Static" or "Steady State" effect, but the behavior is highly time dependent and never stabilizes (goes into Steady State). This means that there is a pressure differential on different parts of the case.
The only part of the case that isn't supported by barrel steel is the case head and more correctly, the sides of the case head as it's backed up by the bolt face.
This is where the case expands when pressures get too high and the brass plastically yields (see Wikipedia for Elastic vs. Plastic deformation). The case head expands and if the pressure curve was steady state the case head would totally fail and the pressure would be released into the action. This still sometimes happens when the case yields too much while the pressures are still high and the primer "sneezes" or backs out totally.
So: The 65ksi spec that I quoted earlier comes from:
I took the Mauser case head configuration and developed a 2D FEM (similar approach to how VarmintAl published on his website with the 243) and I looked at when plastic deformation happened during a pressure curve. I did this with cartridge brass in the nominal state and a M-2sigma reduction in capability for allowables. This gets me to the saying I gave above: 65ksi is a safe limit to shoot the 473 Shell base with a large primer pocket and not suffer brass yield issues and reasonably long brass life.
Remember again, when you hear about overpressure signs in loading and you want to see what's going on, you look at the case head. Look at the primer pocket area, the primer cup itself, the extractor groove dimensions and the web/body interaction surface on the head.
You don't look at the neck and the global region of the body of the case. Why not? This is because the brass is supported by barrel steel where the stress/strain allowables have a significant increase in capability and the load is just passed into the steel from the compliant, thin walled brass.
Now, back to reasonable capability increase of a round for the 308 vs. the 30-06. If you use circa 1950 powders and bullets for 50-55ksi loads in the 30-06 and then load the 308 using the same powders to 60ksi there's no surprise that they are very close. Today those loads are what is known as "managed recoil". Powder burn rate affects cases differently based up on the internal capacity of a case. Hence using Varget or 4895 in the 308 gets great velocity and great results with the 175-180gr bullets. If you tried to use those powders with the same % fill in a 30-06 the "peaky" curve in the 25% larger case volume would become dangerous quite quickly. This is the whole argument towards "proper powder" that we've both agreed makes a difference.
Based on the numbers that I showed above from my tests (where the loads are all held to under 65ksi per the limit that I imposed on both cases) there is a significant (ie double the increases you think aren't worthwhile) increase in capability.
Of course, my statements are totally without merit, cause, or understanding. I simply write out of testing and calculations that both myself and other like minded shooters have performed to glean a better idea of the behavior. I guess that multiple degrees in ME&CM and years of experience doing nit-pick detail failure analysis has taught me nothing.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DP425</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bohem</div><div class="ubbcode-body">This issue is argued here all the time and the people who have actually spent the time/money/sweat to put the myth to bed clearly have demonstrated the behavior between the two rounds.
Here's something else to consider:
Look at the max listed pressures for 22-250, 243, 260, 7mm-08, 270, 280, 30-06 and see what kind of max pressure variance you find.
The case head is identical in all of these cases. That's the governing factor, if it's identical you can push the same peak pressures from all of them.
</div></div>
Then why don't they have the same pressure spec? Right now you are arguing that it's perfectly safe to bump up a lower SPECIFIED chamber pressure so long as the case head is of the same design. Lets take .38 SPC, .38 SPC+P and .357Mag...
SPC: 17,000
+P: 18,500
Mag: 35,000
They share the same design case head- there for you should be able to push a .38 special loading up to 35,000 PSI. I'm not totally sure- <span style="font-weight: bold">I'm not an engineer or anything</span>, but I was under the impression that case pressure is distributed throughout all bearing metal surrounding the case. Just because a cartridge is designed off of another does not mean it is designed to run the same pressure. <span style="font-weight: bold">This where your "understanding" is incomplete</span>
That idea is totally ignorant. Keep your pressures as advertised. No one is disputing that the .30-06 will send a bullet faster, or that it has the capability to chamber heavier (read:longer) bullets. But in-spec loadings do not produce a worthwhile velocity difference within the range of bullets that can be loaded to .308.
If there were no such thing as SAAMI specs, I would be agreeing with you all day long. And I'll even agree with you, that if you hold the .308 to it's pressure specs, but ignore the specs for the .30-06, you'll have note-worthy velocity increase over .308. But staying within SAAMI specs, .30-06's only real advantage is in the ability to throw longer bullets. I'm not saying either is inherently more accurate than the other, but 100-150fps is really nothing to get excited about.
Finally, to the OP- there are MUCH better options available that will not cost you a great deal more for not so much gain. If it were a bolt gun and you wanted to go .30-06 I wouldn't even have posted on here- price difference between a short action and medium/long action rifle otherwise the same is really negligible. So in that respect go with whatever your interested in. But when we're talking about an AR, which would be very rare and unconventional... driving costs up considerably... There are better ways to go (such as some of those short mag's listed above). </div></div>
So you're not an engineer but you're going to give me, the mechanical engineer who's actually modeled time dependent (aka transient state) internal models of the stresses involved in an action, a lesson on how the load paths and yield criteria in a rifle action a developed?
The 38/38+P/357 example you posted is written in total ignorance, if you knew the history of how the 357 and the 44mag were developed you'd already know where those pressure ratings come from.
Here's a short history:
38 shooters decided that more could be gleaned from the modern steels in the big revolvers being produced after WWI. The leaps in military rifles and steels leading up to WWI and thereafter meant that (then) recently produced revolvers with strong top straps and higher strength parts could take more abuse. The initial developments were done on retro-fit pistols meant for the bigger revolver rounds that had been refitted with 38 Spc barrels and chambers.
So, the key contributors to that round started pushing more and more powder into the 38 Spc. cases and seeing how hard things could be pushed.
Clearly this ammo was not meant for the vast majority of the 38's on the market so a geometry change to the cases had to be made so that they could not be mistakenly fired in a "weak" 38. This is why the case was lengthened so that it would not fit in a standard 38 Spc.
The +P is a new designation that was deemed feasible when the magnum handgun craze was sweeping the industry to sell more 38 Spc. ammo. It could be safely shot in the 38's and it simply reduced the safety factor, but the safety factors being set high in this industry the reduction was deemed feasible. Note that the difference between a 38 and 38+P is 1500psi or less than a 10% increase.
357's are literally double the pressure and it's clear why that would not be safe, but also note that the case head didn't change, it was the actual firearm that was limiting the chambering and not the ammunition design.
So, now back to the 30-06 vs. 308 debate. The pressure specs by SAAMI are simply listed and organized by SAAMI. The body does not regulate what a company does when branding or submitting the ammunition for spec publication.
The 22-250 is a Remington "invention" (or appropriately an adoption) while the 308 is an adoption by Winchester. This entitles the respective companies to tie "Remington" or "Winchester" to the name. We don't call the 22-250 the 22-250/300 Savage which is its true lineage, it's named by the company who adopted it and submitted to SAAMI for the spec publication.
So, now, going back to the way pressure is distributed in the case:
Yes, the wetted surfaces inside the case would all see a constant pressure reading in "Static" or "Steady State" effect, but the behavior is highly time dependent and never stabilizes (goes into Steady State). This means that there is a pressure differential on different parts of the case.
The only part of the case that isn't supported by barrel steel is the case head and more correctly, the sides of the case head as it's backed up by the bolt face.
This is where the case expands when pressures get too high and the brass plastically yields (see Wikipedia for Elastic vs. Plastic deformation). The case head expands and if the pressure curve was steady state the case head would totally fail and the pressure would be released into the action. This still sometimes happens when the case yields too much while the pressures are still high and the primer "sneezes" or backs out totally.
So: The 65ksi spec that I quoted earlier comes from:
I took the Mauser case head configuration and developed a 2D FEM (similar approach to how VarmintAl published on his website with the 243) and I looked at when plastic deformation happened during a pressure curve. I did this with cartridge brass in the nominal state and a M-2sigma reduction in capability for allowables. This gets me to the saying I gave above: 65ksi is a safe limit to shoot the 473 Shell base with a large primer pocket and not suffer brass yield issues and reasonably long brass life.
Remember again, when you hear about overpressure signs in loading and you want to see what's going on, you look at the case head. Look at the primer pocket area, the primer cup itself, the extractor groove dimensions and the web/body interaction surface on the head.
You don't look at the neck and the global region of the body of the case. Why not? This is because the brass is supported by barrel steel where the stress/strain allowables have a significant increase in capability and the load is just passed into the steel from the compliant, thin walled brass.
Now, back to reasonable capability increase of a round for the 308 vs. the 30-06. If you use circa 1950 powders and bullets for 50-55ksi loads in the 30-06 and then load the 308 using the same powders to 60ksi there's no surprise that they are very close. Today those loads are what is known as "managed recoil". Powder burn rate affects cases differently based up on the internal capacity of a case. Hence using Varget or 4895 in the 308 gets great velocity and great results with the 175-180gr bullets. If you tried to use those powders with the same % fill in a 30-06 the "peaky" curve in the 25% larger case volume would become dangerous quite quickly. This is the whole argument towards "proper powder" that we've both agreed makes a difference.
Based on the numbers that I showed above from my tests (where the loads are all held to under 65ksi per the limit that I imposed on both cases) there is a significant (ie double the increases you think aren't worthwhile) increase in capability.
Of course, my statements are totally without merit, cause, or understanding. I simply write out of testing and calculations that both myself and other like minded shooters have performed to glean a better idea of the behavior. I guess that multiple degrees in ME&CM and years of experience doing nit-pick detail failure analysis has taught me nothing.
Re: 30-06 AR?
I think what bohem was referring to is the actual case, not the case head dimensions per se. If I'm not mistaken, the .270 (necked down '06) functions at a higher psi than that of the parent case. Therefore, why can't we just take a .270 case, neck it back up to .30, and use it at the previous higher pressure? If the firearm is rated to handle a certain pressure, and the brass is also capable, then there does not appear to be much of an issue. At least that is how I see it and my opinion.
I think what bohem was referring to is the actual case, not the case head dimensions per se. If I'm not mistaken, the .270 (necked down '06) functions at a higher psi than that of the parent case. Therefore, why can't we just take a .270 case, neck it back up to .30, and use it at the previous higher pressure? If the firearm is rated to handle a certain pressure, and the brass is also capable, then there does not appear to be much of an issue. At least that is how I see it and my opinion.
Re: 30-06 AR?
FFL- The only dimension change to the 270 is that it's neck length is longer at a trim length of 2.530 vs. the 2.484 on the 30-06. Your solution is right, just trim about 0.050" off the case and run with it.
The case heads are the weakest link in a modern firearm, that's where the concern for case head geometry comes into play.
FFL- The only dimension change to the 270 is that it's neck length is longer at a trim length of 2.530 vs. the 2.484 on the 30-06. Your solution is right, just trim about 0.050" off the case and run with it.
The case heads are the weakest link in a modern firearm, that's where the concern for case head geometry comes into play.
Re: 30-06 AR?
Bohem- I trust what you say to be true... but I think you're leaving out an important factor... what a specific firearm is designed to handle for pressure. To say the case of a .30-60 should be able to handle 65k psi is one thing... to say the firearm you're firing it out of can handle that pressure is a different story entirely.
As for powders, I was specifically NOT focusing on what powder gave what results- only the results.
I still maintain, a firearm chambered for .30-06 or .308 for that matter should not be subjected to pressures above what the SAAMI spec's are. Over pressure is a quick route to sheared bolt lugs- and that's of course, just the most likely of damage.
It's just mind numbing that you're actually advising to load 7000psi above spec!
Also, I'm well aware of .38... it very well illustrated my point. Some guns may have been over-built and capable of handling the additional pressure- but that was not a universal truth.
Feel free to continue advising hand loading well above the pressure spec- I will continue to advise people stick with the published standards. Those published standards bring the two rounds very close ballistically.
Long story short- sure, if you want to load your ammo in excess of 5000PSI above SAAMI spec, you'll get 200-300fps more than .308. But if you run it to spec, it's closer to 100-150.
Personally, if I want a .30 with near magnum velocity, I'll just buy a magnum instead of running a non-magnum over pressured.
Bohem- I trust what you say to be true... but I think you're leaving out an important factor... what a specific firearm is designed to handle for pressure. To say the case of a .30-60 should be able to handle 65k psi is one thing... to say the firearm you're firing it out of can handle that pressure is a different story entirely.
As for powders, I was specifically NOT focusing on what powder gave what results- only the results.
I still maintain, a firearm chambered for .30-06 or .308 for that matter should not be subjected to pressures above what the SAAMI spec's are. Over pressure is a quick route to sheared bolt lugs- and that's of course, just the most likely of damage.
It's just mind numbing that you're actually advising to load 7000psi above spec!
Also, I'm well aware of .38... it very well illustrated my point. Some guns may have been over-built and capable of handling the additional pressure- but that was not a universal truth.
Feel free to continue advising hand loading well above the pressure spec- I will continue to advise people stick with the published standards. Those published standards bring the two rounds very close ballistically.
Long story short- sure, if you want to load your ammo in excess of 5000PSI above SAAMI spec, you'll get 200-300fps more than .308. But if you run it to spec, it's closer to 100-150.
Personally, if I want a .30 with near magnum velocity, I'll just buy a magnum instead of running a non-magnum over pressured.
Re: 30-06 AR?
OK, then here's a question to explain your 300 WM safety.
The 300 WM is regularly chambered SAFELY by the factory in 700 actions. There is no difference in lug or lug abutment geometry to the 473 or 532 case heads.
300 WM case head area = 0.2229 sqin
30-06 case head area = 0.1757 sqin
Under the same SAAMI spec operating pressures then the 300 WM exhibits 26.5% more bolt thrust.
65ksi/60ksi ~ 9% higher pressure and therefore 9% higher bolt thrust loads.
Which one is safer if you're worried about bolt lug shear? Based on your safety advice, sell the 300 WM off to someone who doesn't care about their face.
OK, then here's a question to explain your 300 WM safety.
The 300 WM is regularly chambered SAFELY by the factory in 700 actions. There is no difference in lug or lug abutment geometry to the 473 or 532 case heads.
300 WM case head area = 0.2229 sqin
30-06 case head area = 0.1757 sqin
Under the same SAAMI spec operating pressures then the 300 WM exhibits 26.5% more bolt thrust.
65ksi/60ksi ~ 9% higher pressure and therefore 9% higher bolt thrust loads.
Which one is safer if you're worried about bolt lug shear? Based on your safety advice, sell the 300 WM off to someone who doesn't care about their face.
Re: 30-06 AR?
I know I will get flamed for this, and it is slightly off topic, but depending on the brass .357 will have thicker brass at the head then 38 spcl, so they do not share the same case head. If you have good 38 brass it can be loaded to near 357 levels in a 357 revolver as long as you seat the bullets way out to maintain C.O.L.
I know I will get flamed for this, and it is slightly off topic, but depending on the brass .357 will have thicker brass at the head then 38 spcl, so they do not share the same case head. If you have good 38 brass it can be loaded to near 357 levels in a 357 revolver as long as you seat the bullets way out to maintain C.O.L.
Re: 30-06 AR?
dog- as you said, depending on the brass... and my argument wasn't against brass construction so much as it is firearm construction
Bohem- are a .300WM and .30-06 Rem 700 EXACTLY the same? Metals the same, dimensions the same?
You can put this any way you want, but it is irresponsible to tell someone it's okay to load a cartridge over 5000psi (actually sounds closer to 7000) over SAAMI Spec. PERIOD.
dog- as you said, depending on the brass... and my argument wasn't against brass construction so much as it is firearm construction
Bohem- are a .300WM and .30-06 Rem 700 EXACTLY the same? Metals the same, dimensions the same?
You can put this any way you want, but it is irresponsible to tell someone it's okay to load a cartridge over 5000psi (actually sounds closer to 7000) over SAAMI Spec. PERIOD.
Re: 30-06 AR?
Yes, the locking geometry is identical. The material is the same.
Changes in the action don't happen until the Lapua Mag cases where they go to a larger diameter bolt body. I have some reservations about putting that much bolt thrust through a 700 and maintaining conservative margins but that's a different topic to discuss.
Yes, the locking geometry is identical. The material is the same.
Changes in the action don't happen until the Lapua Mag cases where they go to a larger diameter bolt body. I have some reservations about putting that much bolt thrust through a 700 and maintaining conservative margins but that's a different topic to discuss.
Re: 30-06 AR?
I wasn't trying to imply that the .270 and '06 dimensions were interchangeable. Just that what were once wildcats based on the same '06 case, yet at different pressures are now acceptable, even at higher pressures than that of the parent case. Not that you need any explanation on the topic. Just trying to help others understand our collective position on the topic.
I wasn't trying to imply that the .270 and '06 dimensions were interchangeable. Just that what were once wildcats based on the same '06 case, yet at different pressures are now acceptable, even at higher pressures than that of the parent case. Not that you need any explanation on the topic. Just trying to help others understand our collective position on the topic.
Re: 30-06 AR?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bohem</div><div class="ubbcode-body">Yes, the locking geometry is identical. The material is the same.
Changes in the action don't happen until the Lapua Mag cases where they go to a larger diameter bolt body. I have some reservations about putting that much bolt thrust through a 700 and maintaining conservative margins but that's a different topic to discuss. </div></div>
Well, then that would make me more trusting in that particular rifle's ability to contain the pressure. However, I believe my point still rings true- it's never truly advisable to exceed specified max chamber pressure. In other words, it is a very much proceed at your own risk situation and IMO, if you are going to advise people that's a good way to get some extra speed, you should also inform them of the POSSIBLE implications.
So, putting aside hand-loading to pressures higher than any reputable factory loading will give you... the difference isn't very much.
Either way, it would seem no matter if it's 100-160fps or 150-280fps difference, seems we can all agree that the extra cost that would be associated in such an adventure simply is not worth the gain when there are other viable alternatives (and not likely to be worth it even if there were no other alternatives- at some point desires need to meet practical reality)
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bohem</div><div class="ubbcode-body">Yes, the locking geometry is identical. The material is the same.
Changes in the action don't happen until the Lapua Mag cases where they go to a larger diameter bolt body. I have some reservations about putting that much bolt thrust through a 700 and maintaining conservative margins but that's a different topic to discuss. </div></div>
Well, then that would make me more trusting in that particular rifle's ability to contain the pressure. However, I believe my point still rings true- it's never truly advisable to exceed specified max chamber pressure. In other words, it is a very much proceed at your own risk situation and IMO, if you are going to advise people that's a good way to get some extra speed, you should also inform them of the POSSIBLE implications.
So, putting aside hand-loading to pressures higher than any reputable factory loading will give you... the difference isn't very much.
Either way, it would seem no matter if it's 100-160fps or 150-280fps difference, seems we can all agree that the extra cost that would be associated in such an adventure simply is not worth the gain when there are other viable alternatives (and not likely to be worth it even if there were no other alternatives- at some point desires need to meet practical reality)
Re: 30-06 AR?
I'm not disagreeing that an AR in 30-06 is going to cripple the 30-06 case and a different application would suit it better. My disagreement came from the comments regarding the 308 and 30-06 comparison and where it spiraled from there.
There have been some AR10 size conversions to shoot the 300 SAUM which is a very close copy ballistically.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ffl medic</div><div class="ubbcode-body">I wasn't trying to imply that the .270 and '06 dimensions were interchangeable. Just that what were once wildcats based on the same '06 case, yet at different pressures are now acceptable, even at higher pressures than that of the parent case. Not that you need any explanation on the topic. Just trying to help others understand our collective position on the topic. </div></div>
Gotcha, I saw where you were going with it. No worries.
I'm not disagreeing that an AR in 30-06 is going to cripple the 30-06 case and a different application would suit it better. My disagreement came from the comments regarding the 308 and 30-06 comparison and where it spiraled from there.
There have been some AR10 size conversions to shoot the 300 SAUM which is a very close copy ballistically.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ffl medic</div><div class="ubbcode-body">I wasn't trying to imply that the .270 and '06 dimensions were interchangeable. Just that what were once wildcats based on the same '06 case, yet at different pressures are now acceptable, even at higher pressures than that of the parent case. Not that you need any explanation on the topic. Just trying to help others understand our collective position on the topic. </div></div>
Gotcha, I saw where you were going with it. No worries.
Re: 30-06 AR?
Not precisely what you had in mind, but along similar lines; the Saiga 100. Also, the Remington 750.
Not precisely what you had in mind, but along similar lines; the Saiga 100. Also, the Remington 750.
Re: 30-06 AR?
I own one of the original Cobb MCR 30-06 produced by Skip Patel; now at BM. It utilizes the WW2 BAR magazines which can be troublesome. Other than that, its a hell of an AR. One bad point; it does not have a bolt hold open catch.
And its long and heavy, but a riot to shoot. As an FYI: only 100 were made as a 100th anniversary tribute to the 30-06 cartridge.
Sorry if this info has been repetitive...but all in all; fun rifle!
I own one of the original Cobb MCR 30-06 produced by Skip Patel; now at BM. It utilizes the WW2 BAR magazines which can be troublesome. Other than that, its a hell of an AR. One bad point; it does not have a bolt hold open catch.
And its long and heavy, but a riot to shoot. As an FYI: only 100 were made as a 100th anniversary tribute to the 30-06 cartridge.
Sorry if this info has been repetitive...but all in all; fun rifle!
Re: 30-06 AR?
Everyone can stop arguing and waving their small penises. Bushmaster will soon be producing the Cobb MCR again soon. In 30-06 as a option as well. Problem solved, curiosity subsided, new ideas processing. Thread should be locked.
Everyone can stop arguing and waving their small penises. Bushmaster will soon be producing the Cobb MCR again soon. In 30-06 as a option as well. Problem solved, curiosity subsided, new ideas processing. Thread should be locked.
Re: 30-06 AR?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GoatHead</div><div class="ubbcode-body">Everyone can stop arguing and waving their small penises. Bushmaster will soon be producing the Cobb MCR again soon. In 30-06 as a option as well. Problem solved, curiosity subsided, new ideas processing. Thread should be locked. </div></div>
Why lock it when it is already done?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GoatHead</div><div class="ubbcode-body">Everyone can stop arguing and waving their small penises. Bushmaster will soon be producing the Cobb MCR again soon. In 30-06 as a option as well. Problem solved, curiosity subsided, new ideas processing. Thread should be locked. </div></div>
Why lock it when it is already done?
