Powder Choices With Longer Barrels? Will Slower Powders Extend or Shorten Barrel Burnout?

[arakboss]

I have read that you can use slower powders as barrel length increases. Generally load data books list data for one barrel length.

Would there be much difference in the powder selection available when reloading for a 24" 223/5.56 barrel vs a 18" 223/5.56 barrel?

Will slower powders impact the barrel life?

Read More

 

[TTSX]

Much difference in powders? Probably not. Certainly a difference in the efficiency of burn. It's not like you'd jump from 3031 to H1000, though I'm sure you could take SOME advantage of a slightly slower burning powder in the longer barrel, especially if heavy bullets are used.

As for barrel life, yeah there's more than likely a difference. Enough of a difference to make a difference? You be the judge. AR barrels are cheap, burn 'em up.

 

[arakboss]

Much difference in powders? Probably not. Certainly a difference in the efficiency of burn. It's not like you'd jump from 3031 to H1000, though I'm sure you could take SOME advantage of a slightly slower burning powder in the longer barrel, especially if heavy bullets are used.

As for barrel life, yeah there's more than likely a difference. Enough of a difference to make a difference? You be the judge. AR barrels are cheap, burn 'em up.

I was thinking of trying out some IMR4831speed powder with a 77gr bullet in a cheapo 20" barrel I have now. One thread I read on another forum suggested too slow of a powder for a cartridge could cause ringing in the barrel. Not sure how likely that is to occur?

I would expect pressure and velocity to be low with IMR4831 speed powder, which should aid in barrel life?

Slower powders seem to be easier to find these days and I have a fair amount of them on hand now.

I am not concerned with getting max velocities. A decent bull barrel purchase is in my future. I was looking at 20 inchers but might go with 24 incher if I expect to run slower powders very often.

 

[oremike]

I haven't any data to back up my thoughts on this but here goes anyway, I want the pwder to burn as long as possable in the barrel. As long as the powder is generating gas (burning) it's building pressure. The a heavier bullet (200gr Nosler Partition), longer barrel(26") and slower powder(retumbo) combination is what I set up for my 300 win mag. For my .223 bolt gun I did the opposite, light for caliber bullet (50gr Speer TNT), faster powder (Win 748) and it's got a 20" barrel.

 

[clueless]

I haven't any data to back up my thoughts on this but here goes anyway, I want the pwder to burn as long as possable in the barrel. As long as the powder is generating gas (burning) it's building pressure. The a heavier bullet (200gr Nosler Partition), longer barrel(26") and slower powder(retumbo) combination is what I set up for my 300 win mag. For my .223 bolt gun I did the opposite, light for caliber bullet (50gr Speer TNT), faster powder (Win 748) and it's got a 20" barrel.

20" is a great length for a 223 barrel and all 223 ammo will produce a higher muzzle velocity with 20" barrel than a similar barrel cut shorter.

That said, the improvement continues for most ammo with even longer barrels. As far as using slow powders, one can go too slow and lose accuracy if the powder is not completely burnt by the time the bullet exits. Software such as QuickLoad gives estimates on % powder burned for various conditions, including barrel length. It can be surprising to see that sometimes even medium speed powders are not fully burned in seemingly long barrels.

The long barrels provide the most benefit when shooting heavier charges of slower powder. In another post I gave an example of shooting a 75gr hornady bullet in a 223 Rem Savage with 26" 1:9 twist barrel and N140. The most accurate load that I found leaves the barrel at around 2920 fps. That is at least 250 fps faster than the 20" service rifles are achieving with the same bullet.

As far as slower burning powders affecting barrel life, I believe that George Gardner said that single-base powders had the advantage when it comes to barrel life. This is not the same as fast/slow burn rate, but might be helpful in selecting a powder if barrel life is of concern.

 

[P7M13]

I haven't any data to back up my thoughts on this but here goes anyway, I want the pwder to burn as long as possable in the barrel. As long as the powder is generating gas (burning) it's building pressure. The a heavier bullet (200gr Nosler Partition), longer barrel(26") and slower powder(retumbo) combination is what I set up for my 300 win mag. For my .223 bolt gun I did the opposite, light for caliber bullet (50gr Speer TNT), faster powder (Win 748) and it's got a 20" barrel.

I'm in the same boat. I also look at bearing surface of the bullet.

 

[osprey]

Generally speaking, the powders that give the best velocity in a longer barrel, will do the same in a shorter barrel. This has been my experience, but there are too many variables to say it is absolutely true. If we are talking super short barrels, like under 6", this may not hold true. Bullet design, type of powder, twist rate and several other factors can also skew the results. Changing to a faster burning powder can lessen the fireball in shorter barrels. As always ymmv.

 

[Cerberus Group]

Speed- Velocity kills barrels.

What's the average barrel life of a 22-250 vs a 7mm Mauser etc.?

You might get 2-4,000 rounds out of a factory 22-250 barrel vs a slower velocity round which would go way past that.

I know, someone is going to come up with a...but mine has lasted well past 50,000 rounds with no noticeable decrease in accuracy. Pleeeeez

Point being there's a trade-off to pushing the velocity to Mach 42...

 

[dangerranger60]

I would think the fastest powders would be first to cause erosion in the first inch or so of a barrel. The burn is hottest just as the bullet leaves the case.
Slower powders take advantage of the longer barrel by burning longer and continuing to expand as the bullet goes down barrel. instead of concentrating that heat in the first few inches. DR

 

[JRuby]

A longer barrel with the same powder should produce a higher velocity up to a point. I am more concerned about chamber pressure and I have no way to measure chamber pressures until i have stiff extraction or primers start showing issues. I have always been more concerned about accuracy then I have been about velocity. I will stay with reccomended loads. Very rarely have I found maximum loads producing the best accuracy..