I'm looking for some education on fast vs. slow burning powders in loading for my 280AI. It seems the majority of the charges shown in the reloading manuals is for powders toward the lower end of the burn rate chart. What is the result if you moved up the chart to one of the faster burning powders?
- Thread starter Brent Thornton
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Re: fast vs. slow burning powders...question
Depends on your rifle. Most folks that do the improved route wish to speed up their bullets and lengthen the life of the brass. All that is done with powder that is slower than is usual for the chamber/caliber. Since you have gone to the expense of improving the chamber, you really need to go to a slower than normal .280 W powder loading. I may be reading into this thread more than is intended, but I get the impression that you want to use fast powder so that you can get more rounds per pound. You negated that option when you went to the IMPROVED chamber. Bite the bullet and load slower than usual powders for the .280. JMHO
Depends on your rifle. Most folks that do the improved route wish to speed up their bullets and lengthen the life of the brass. All that is done with powder that is slower than is usual for the chamber/caliber. Since you have gone to the expense of improving the chamber, you really need to go to a slower than normal .280 W powder loading. I may be reading into this thread more than is intended, but I get the impression that you want to use fast powder so that you can get more rounds per pound. You negated that option when you went to the IMPROVED chamber. Bite the bullet and load slower than usual powders for the .280. JMHO
Re: fast vs. slow burning powders...question
Most powders from H or I 4350 will work fine. The faster the burn rate, the more air space you'll have in the case. I'd try RL-22 or H4831 first.
Most powders from H or I 4350 will work fine. The faster the burn rate, the more air space you'll have in the case. I'd try RL-22 or H4831 first.
Re: fast vs. slow burning powders...question
basically, when you increase bullet weight in a given caliber, you will also go to a slower powder. You can use a faster powder with the heavier bullets, but you will reach peak presure before you get to max velocity. The lighter bullets exit the barrel much faster than the heavier bullets, and need a faster powder to get to peak pressure. The heavier bullets also have a longer bearing surface, and will build up more pressure with a faster powder.
basically, when you increase bullet weight in a given caliber, you will also go to a slower powder. You can use a faster powder with the heavier bullets, but you will reach peak presure before you get to max velocity. The lighter bullets exit the barrel much faster than the heavier bullets, and need a faster powder to get to peak pressure. The heavier bullets also have a longer bearing surface, and will build up more pressure with a faster powder.
Re: fast vs. slow burning powders...question
Thanks for the replys and information, wanted to to make sure that my thought process was correct.
Thanks for the replys and information, wanted to to make sure that my thought process was correct.
Re: fast vs. slow burning powders...question
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">basically, when you increase bullet weight in a given caliber, you will also go to a slower powder. You can use a faster powder with the heavier bullets, but you will reach peak presure before you get to max velocity. The lighter bullets exit the barrel much faster than the heavier bullets, and need a faster powder to get to peak pressure. The heavier bullets also have a longer bearing surface, and will build up more pressure with a faster powder. </div></div>
Good explanation Chad.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">basically, when you increase bullet weight in a given caliber, you will also go to a slower powder. You can use a faster powder with the heavier bullets, but you will reach peak presure before you get to max velocity. The lighter bullets exit the barrel much faster than the heavier bullets, and need a faster powder to get to peak pressure. The heavier bullets also have a longer bearing surface, and will build up more pressure with a faster powder. </div></div>
Good explanation Chad.
Re: fast vs. slow burning powders...question
Because longer barrels give the bullet further to travel, more time is available for the propellent to burn, so slower powders can also be also indicated for longer barrels.
Also, less airspace in the case often equates to better accuracy, so using a slower powder to get a larger charge into the case can also indicate a use for slower powders.
Conversely, faster powders and lighter bullets will usually get the best performance out of a shorter barrel. This is an application where longer, lighter weight solid copper bullets with their higher BC's than comparable weight lead core bullets can be of a significant advantage. Just remember, ideal twist is a function of length, not weight.
Greg
Because longer barrels give the bullet further to travel, more time is available for the propellent to burn, so slower powders can also be also indicated for longer barrels.
Also, less airspace in the case often equates to better accuracy, so using a slower powder to get a larger charge into the case can also indicate a use for slower powders.
Conversely, faster powders and lighter bullets will usually get the best performance out of a shorter barrel. This is an application where longer, lighter weight solid copper bullets with their higher BC's than comparable weight lead core bullets can be of a significant advantage. Just remember, ideal twist is a function of length, not weight.
Greg
Re: fast vs. slow burning powders...question
Some posted responses are a little off target.
In short, the idea of solwer burning propellants is to keep peak pressures sustained for a longer period of time,with those pressures rising slower-given a heavier projectile, hence the use of longer barrels.
Basics here; http://www.frfrogspad.com/intballi.htm
There is a powder burn chart on a link within that article.
NEVER, ABOSOLUTELY NEVER- USE A BURN CHART TO START A LOAD.
Thats what reloading manuals are for.
And if you like that there is some cool stuff here: http://www.shootingsoftware.com/pressure.htm
Some posted responses are a little off target.
In short, the idea of solwer burning propellants is to keep peak pressures sustained for a longer period of time,with those pressures rising slower-given a heavier projectile, hence the use of longer barrels.
Basics here; http://www.frfrogspad.com/intballi.htm
There is a powder burn chart on a link within that article.
NEVER, ABOSOLUTELY NEVER- USE A BURN CHART TO START A LOAD.
Thats what reloading manuals are for.
And if you like that there is some cool stuff here: http://www.shootingsoftware.com/pressure.htm
Re: fast vs. slow burning powders...question
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">basically, when you increase bullet weight in a given caliber, you will also go to a slower powder. You can use a faster powder with the heavier bullets, but you will reach peak presure before you get to max velocity. The lighter bullets exit the barrel much faster than the heavier bullets, and need a faster powder to get to peak pressure. The heavier bullets also have a longer bearing surface, and will build up more pressure with a faster powder. </div></div>
Good explanation Chad. </div></div>
I would like to add there other factors like bullet diam and bearing surface that can change what rate of powder you use.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">basically, when you increase bullet weight in a given caliber, you will also go to a slower powder. You can use a faster powder with the heavier bullets, but you will reach peak presure before you get to max velocity. The lighter bullets exit the barrel much faster than the heavier bullets, and need a faster powder to get to peak pressure. The heavier bullets also have a longer bearing surface, and will build up more pressure with a faster powder. </div></div>
Good explanation Chad. </div></div>
I would like to add there other factors like bullet diam and bearing surface that can change what rate of powder you use.
Re: fast vs. slow burning powders...question
Specifically on this subject I've was doing load development with IMR 4831 and a 140vld not getting the accuracy that I expected from the rifle. On a suggestion from an experienced reloader I swithced to IMR 4007 SSC and at various powder charges on a 140 vld was receiving better groups, 4, 3 shot groups were about .4 better at a 100 yards with all other components similar. The 4007ssc is a considerably faster burning powder than the 4831. It concerns me. I don't have a chronograph yet, so right now the feedback is accuracy, and I usually take the average of 4, 3 shot groups.
Specifically on this subject I've was doing load development with IMR 4831 and a 140vld not getting the accuracy that I expected from the rifle. On a suggestion from an experienced reloader I swithced to IMR 4007 SSC and at various powder charges on a 140 vld was receiving better groups, 4, 3 shot groups were about .4 better at a 100 yards with all other components similar. The 4007ssc is a considerably faster burning powder than the 4831. It concerns me. I don't have a chronograph yet, so right now the feedback is accuracy, and I usually take the average of 4, 3 shot groups.
Re: fast vs. slow burning powders...question
While loading for the .45 ACP I experimented with most of the usual powders and bullet weights. What I found and was told is that fast powders burn completely before the bullet exits the barrel, giving very consistent, but lower velocities. The slower powders don't always complete combustion before the bullet exits, but overall give higher velocities.
While loading for the .45 ACP I experimented with most of the usual powders and bullet weights. What I found and was told is that fast powders burn completely before the bullet exits the barrel, giving very consistent, but lower velocities. The slower powders don't always complete combustion before the bullet exits, but overall give higher velocities.
Re: fast vs. slow burning powders...question
I too would try RL 22 or H4831sc.
I too would try RL 22 or H4831sc.
Re: fast vs. slow burning powders...question
I acutally have loaded up some 22 and 4831sc to experiment with along with some n160
I acutally have loaded up some 22 and 4831sc to experiment with along with some n160
Re: fast vs. slow burning powders...question
Have you tried a different bullet? 4350 to 4831 should be find in a .280AI. I had a 7mm RM that shot 150 grain corelocks in 8 inch circle at 100 yards. With no other changes that would put 168 SMK into a 3/4 inch group. YMMV
Good luck
Jerry
Have you tried a different bullet? 4350 to 4831 should be find in a .280AI. I had a 7mm RM that shot 150 grain corelocks in 8 inch circle at 100 yards. With no other changes that would put 168 SMK into a 3/4 inch group. YMMV
Good luck
Jerry
Re: fast vs. slow burning powders...question
Jerry,
Can get an avg. of .6 with 4, 3 shot groups with 140vld, a .7 avg. with 4 3 shot groups with a 150 combined technology. It's killing either way, just doing a lot testing.
Jerry,
Can get an avg. of .6 with 4, 3 shot groups with 140vld, a .7 avg. with 4 3 shot groups with a 150 combined technology. It's killing either way, just doing a lot testing.
Re: fast vs. slow burning powders...question
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Because longer barrels give the bullet further to travel, more time is available for the propellent to burn, so slower powders can also be also indicated for longer barrels.
</div></div>
Slow powder or fast powder , all powders burn within the first 2" to 3" of the barrel.
The gas created keeps expanding.
<span style="color: #FF0000">The same powders that produce the most velocity with a longer barrel also produce the highest velocities with a shorter barrel. This is because almost all smokeless powder burns within a short distance in front of the chamber.</span>
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Conversely, faster powders and lighter bullets will usually get the best performance out of a shorter barrel.</div></div>
The least velocity loss in shorter barrels is generally with heavier bullets and the slowest powders.
This question normally come up....
"So what about the ball of flame coming out the barrel?"
The ball of flame is the hot gas from the powder reigniting when it hits the oxygen of the atmosphere it's NOT still-burning powder.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Because longer barrels give the bullet further to travel, more time is available for the propellent to burn, so slower powders can also be also indicated for longer barrels.
</div></div>
Slow powder or fast powder , all powders burn within the first 2" to 3" of the barrel.
The gas created keeps expanding.
<span style="color: #FF0000">The same powders that produce the most velocity with a longer barrel also produce the highest velocities with a shorter barrel. This is because almost all smokeless powder burns within a short distance in front of the chamber.</span>
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Conversely, faster powders and lighter bullets will usually get the best performance out of a shorter barrel.</div></div>
The least velocity loss in shorter barrels is generally with heavier bullets and the slowest powders.
This question normally come up....
"So what about the ball of flame coming out the barrel?"
The ball of flame is the hot gas from the powder reigniting when it hits the oxygen of the atmosphere it's NOT still-burning powder.
Re: fast vs. slow burning powders...question
Okay, good luck.
Okay, good luck.
Re: fast vs. slow burning powders...question
Ramshot lists loads for the .280 using Hunter for bullets of 130gr and over, Big Game for under 130gr.
Ramshot lists loads for the .280 using Hunter for bullets of 130gr and over, Big Game for under 130gr.
Re: fast vs. slow burning powders...question
Years ago Chet Brown of Brown Precision Stocks did some experiments with the .270 Win to find the optimum loading for his short, lightweight hunter barrels. His statement at the end was that whatever worked best in the standard barrels also worked best in the shorter barrels. His choice was 4831 in the .270 Win for long or short barrels.
Years ago Chet Brown of Brown Precision Stocks did some experiments with the .270 Win to find the optimum loading for his short, lightweight hunter barrels. His statement at the end was that whatever worked best in the standard barrels also worked best in the shorter barrels. His choice was 4831 in the .270 Win for long or short barrels.
Re: fast vs. slow burning powders...question
I know there sister company's but IMR or H on the 4831?
I know there sister company's but IMR or H on the 4831?
Re: fast vs. slow burning powders...question
In the day it was Hodgson. I don't believe IMR 4831 was available then. IMR came out and was a bit faster than H. Then new production H appeared from Australia. Now H owns IMR and maybe the twain shall meet. Seems like the best advice is to start a bit low...use a manual, and work up. Too low and I understand you can risk a detonation with the heavily coated powders.
In the day it was Hodgson. I don't believe IMR 4831 was available then. IMR came out and was a bit faster than H. Then new production H appeared from Australia. Now H owns IMR and maybe the twain shall meet. Seems like the best advice is to start a bit low...use a manual, and work up. Too low and I understand you can risk a detonation with the heavily coated powders.
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