Possible 7mm Magnum Build?

[MitchInOR]

After re-reading Zak Smith's LR article again about caliber choices I tried plugging my last field conditions into JBM with some .284 bullet/velocities. With 162 amax and 168 vld at 3000fps it is staying supersonic out to 1800 yds, with the amax slightly edging out the vld.
I would like to reach out a little farther than my 308 is capable of.
Are these velocities and distances realistic with a 7mm mag or should I be looking at some thing else?
Will the above bullets hold moa accuracy out to that far?
The 7mm looks to be nearly the same dimensions as 300wm just shorter. Will the 7mm work in an ACIS mag?
Last, I don't know a lot about Remington actions, is there any difference I should look for in a donor action.

 

[Bacarrat]

Re: Possible 7mm Magnum Build?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MitchinOR</div><div class="ubbcode-body">
Are these velocities and distances realistic with a 7mm mag or should I be looking at some thing else?</div></div>
With the 162s and 168s 3k FPS should be easy to do with a 24-26" barrel. I have run them way faster then that out of my WSM, the RM will hold a little bit more powder.
There are a couple of people that are running them 3200+ FPS with the 162s. Also look into the 175-180gr class of bullets too.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">
Will the above bullets hold moa accuracy out to that far?</div></div>
It will be more you then the rifle and bullets.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">
The 7mm looks to be nearly the same dimensions as 300wm just shorter. Will the 7mm work in an ACIS mag?</div></div>
Yes
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">
Last, I don't know a lot about Remington actions, is there any difference I should look for in a donor action. </div></div>
Remington long action with a magnum bolt face and you are good to go.

 

[Terry Cross]

Re: Possible 7mm Magnum Build?

Mitch,

The 7mm Rem Mag will easily cruise those bullets at that speed. With a proper chamber, the 7mm Mag is a killer long range cartridge. It will easily outperform the 7WSM when both use heavy bullets and do with with lower pressures and the ability to chase your lands a little as it wears.

I am going to run a mixed batch of .300Win Mag and 7mm Rem Mag on the new Surgeon Long Action Tactical in the near future. I don't think the 7mmRem Mag is heavily entrenched in the tactical/long range community but come shooters that want to cross over and do some hunting with the same rifle may bite. There are some die hard 7 Mag hunters out there.

Use the right chamber and barrel combination and you will be really happy.

 

[ZLBubba]

Re: Possible 7mm Magnum Build?

Terry,

Could you elaborate more on a "proper chamber" for me? My 7mm RM is getting due for a a rebarrel and since I'm reloading now, I was leaning toward a little heavier contour and tighter chamber. Any ideas?

 

[Sendero_Man]

Re: Possible 7mm Magnum Build?

for hunting weight rifle, I really like the Sendero contour. 26" length.

still good packing weight and shooting the 168 VLD or 162 Amax are an excellent LR hunting rifle. Great caliber and I think Terry is on to something.

I run the 168's at 3040fps at 4895asl. about 20 moa at 1000 yards with 200 zero.

 

[MitchInOR]

Re: Possible 7mm Magnum Build?

Thanks, this sounds like I am on the right track.

It looks like I was missing the 180vld. I am assuming the 162-168 can be pushed faster than the 180. Does the faster fps of the lighter bullets over come the slightly higher bc of the 180?

Also interested in the answer to ZLBubba's question.

 

[7mmRM]

Re: Possible 7mm Magnum Build?

I hear pretty good things about the 7mmRM.....

 

[MitchInOR]

Re: Possible 7mm Magnum Build?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 7mmRM</div><div class="ubbcode-body">I hear pretty good things about the 7mmRM.....

</div></div>

I figured you might have.

 

[Tucsondave]

Re: Possible 7mm Magnum Build?

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1346176

Any interest in this??

 

[RobG]

Re: Possible 7mm Magnum Build?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MitchinOR</div><div class="ubbcode-body">After re-reading Zak Smith's LR article again about caliber choices I tried plugging my last field conditions into JBM with some .284 bullet/velocities. With 162 amax and 168 vld at 3000fps it is staying supersonic out to 1800 yds, with the amax slightly edging out the vld.
I would like to reach out a little farther than my 308 is capable of.
Are these velocities and distances realistic with a 7mm mag or should I be looking at some thing else?
Will the above bullets hold moa accuracy out to that far?
The 7mm looks to be nearly the same dimensions as 300wm just shorter. Will the 7mm work in an ACIS mag?
Last, I don't know a lot about Remington actions, is there any difference I should look for in a donor action. </div></div>

3K + shouldn't be an issue. I run 67 grains of R22 under the amax and based on come ups at 1k yds I am a bit over 3k with no pressure issues.
MOA on a properly built gun, with a developed load, and you on your game, should not be an issue.
You will need a long action with magnum bolt face donor gun, .264 win mag, 7mm, 300 wm, and <span style="font-style: italic">I think </span>.375 HH.
I have thought about trying the 180's but it shoots so good as is, I hate to mess with a good thing.

 

[wnroscoe]

Re: Possible 7mm Magnum Build?

Mitch,
I've had several 7mmRM's and currently shoot a 7-300wsm. I think what Terry is saying holds true with any caliber. Simply decide on a COAL with the bullet you plan to shoot and have the rifle chambered to match your dummy round. If you don’t have a preference as far as OAL just make sure it'll feed in the magazine and there's not too much bullet in or out of the case. When possible, the base of the bullets bearing surface is best placed above the neck shoulder juncture point. Some cartridges wont allow this and magazine feed at the same time. For some tactical / hunting rifles, there may have to be a happy medium.

FYI, I’ve read that the secret service employed the 7mmRM at one time in a role they called "counter sniper rifle"

 

[Glen Seekins]

Re: Possible 7mm Magnum Build?

I would go WSM, we all shoot 162's and 180's plenty fast. I run a 23" barrel and the 162's shoot awsome at 3200fps..
We just got done with our WSM DBM's and i am testing one out today. 3.15" inside the mag, so your options just got a bit more complex

 

[wnroscoe]

Re: Possible 7mm Magnum Build?

Nice rifles Glen.

 

[RobG]

Re: Possible 7mm Magnum Build?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wnroscoe</div><div class="ubbcode-body">Nice rifles Glen. </div></div>

Very nice. What brand of base and rings do you run??

 

[ZLBubba]

Re: Possible 7mm Magnum Build?

Man, now you've got me really thinking about how I want to upgrade my 7mm! Truthfully, though, I could pretty much start anywhere on the thing because it's just a stock Rem700 magnum action. Can't be $370 used at the local gun store. I probably need to start with a new stock. I hate the plastic-y one it has now.

 

[ohiogunnut]

Re: Possible 7mm Magnum Build?

I was shooting 308 primarily, but after looking into the ballistics, went with the 7mm RM myself.

http://www.snipershide.com/forum/ubbthre...000#Post1354000

 

[Graham]

Re: Possible 7mm Magnum Build?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MitchinOR</div><div class="ubbcode-body">...I would like to reach out a little farther than my 308 is capable of. Are these velocities and distances realistic with a 7mm mag or should I be looking at some thing else?</div></div>I re-read what you first wrote, and now I'm going to be the lone dissenter here: If you just want to reach out a bit farther than a capable .308 you should be looking at something else.

Why? Because you don't need a magnum. And you probably don't really want a magnum anyway. 7mm Mag is a game changer: it will surpass the .308's and most everything else out there. So it's fine, but how much recoil do you want to put up with? I have a 300WM that shoots bugholes at 300, and stays supersonic to over 1800 yards. I use it a lot, but it has 265 rounds through it from date of purchase. Meaning: if you're driving 162's at 3200fps you won't be attending any courses with it or shooting it 100 rounds a day at a match.

The 7mm caliber is an excellent choice if you want to keep recoil levels to about that of a .308. 6.5mm is better if you want high velocities but don't like recoil. So, first look to any of the the 6.5's for better performance than a .308. Then look to .284 Win if you want to run 162 AMAX from a short action or 180 VLD's from a long action.

So maybe your first decision should not be caliber choice, but action and size: what type; short, or long?

Check out the Gen II Templar action: head and shoulders above the Remington in all respects. The other aftermarket repeater actions, like Lawton and Stiller, are also good - and a good value if found here on the group buys.

Actions: http://www.6mmbr.com/actions.html

If you are on a budget the Remmy you have will do fine, just make sure it's more or less square on the bottom and not sprung by removal of the factory barrel.

And with regard to your question about the 168's vs 180's, either will do. Bryan Litz has relevant info and test results for you here:
http://bryanlitz.bravehost.com/articles/7mmNumberTwo.pdf

In sum, why not stay with the recoil of the .308, but move up to the superior BC and acceptable barrel life of a 7mm? You can get everything you say want with 168VLD's at 2850fps, and be able to shoot comps with it, too.

 

[steelcomp]

Re: Possible 7mm Magnum Build?

I've been thinking about the 7mm RM. I currently have a Ruger AllWeather synthetic/stainless in 7mm RM and that rifle shot .75 moa right out of the box with plain old PMC 140g PSP's. This is one of my hunting rifles and for northern CA blacktails we shoot Hornaday Custom 139g InterBond Moly's. Pretty impressive performance down range. MV/ME 3250/3259 200yd 2845/2498 500yd 2301/1634. I'm new to ballistics, so I don't know where this plays into longer range shooting, but for our </= 500yd cross-canyon shots, it's the best overall performing 7mm round. It does have a bit of a kick, though.
Would the Ruger platform be a cantidate for converting into a LR tactical/sniper type platform?
TIA

 

[18Echo]

Re: Possible 7mm Magnum Build?

I'm having a 7mmRM built for me by Gary Ocock. If I had to do it again though I think I would build a straight .284 winchester.

Is there such a thing as a .30-06 case necked down to accept a .284 bullet, or is that the .284 Winchester?

 

[DMann]

Re: Possible 7mm Magnum Build?

The .30-06 necked down to 7mm is known as the .280. The .284 is its own case and never existed before the 50's when Winchester tried to match .270 ballistics in its M88 "modern" lever action and M100 semiauto. The case body is close to magnum width and it uses a rebated rim (.473 case head) to get the case capacity to push the bullets hard while still working through a short action.

Mind you, the bullets have to be shoved back into the case a bit to keep COAL within a short mag box. A .284 on a long action makes sense.

 

[steelcomp]

Re: Possible 7mm Magnum Build?

Would this work?
Savage 112 BVSS 7mm RemMag

 

[MitchInOR]

Re: Possible 7mm Magnum Build?

Sorry for not coming back to my thread faster. Thanks for all the response to this thread.
William I really appreciate your comments on chambering for specific oal and optimum seating depth.
Glen you make some awesome products and if I don't buy a stock with an acis mag in already I would definitely consider yours.
Any time a question is asked about a specific cartridge there will always be debate over what is better. I don't think there is any single solution but lots of options. If that wasn't so we would all be shooting the same rifle.
The article comparing the 168-180 vld was interesting. It makes it look like the light bullet is the way to go, yet a lot of people use the 180.
I would really like to hear more about the 162 amax and how it compares to the Berger bullets.

 

[Limbic]

Re: Possible 7mm Magnum Build?

I shot the 162amax, 168berger, 180berger alot in the last year. I've probably loaded over 750-1000 rds for my 7mag in the past 12 months.

I found my gun likes the VLD type bullets at about 3000fps. I shot over 400 168VLD and could never get good consistent groups over 3000fps. Consistent is the key word. Also if I'm not shooting 1/2MOA I'm not happy.

So in order to meet my MV criteria I loaded up some 180VLD's with 68g Retumbo. Last group I shot was 1.2" at 300yrds. I just about gave up trying different loads because this one always brings home the bacon.

Ballistic FTE on my Iphone show the energy at 300 yrds still above 2600 (2614 footpounds I think) This is just about 40 footpounds less than factory 200g Accubond from a 300 win Mag.