Powder & Short Barrels..

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R

RN

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Hey guys..

My carry weapon is a Gen 4 10mm G29 and I shoot it like a 1911...It's a very comfortable weapon in my hands but now that I am all about reloading I need some advice from the pros..

For range time I will throw in a .40 conversion barrel and go to town..For personal carry I throw in factory 10mm..I am learning that my roll your own loads are better.

So.....I know how to load it according to the "books" but how do these loads differ when it comes to short barrels? Faster powder? Slower Powder? Etc...
 
It doesn't matter.

Whatever powder in the manual gives the highest velocity in a long barrel will also give the highest velocity in a short barrel.

You don't pick powders based on barrel length.

You pick powders based on the one that gives the highest velocity, or best accuracy in the load manuals.
Depending on your needs.

rc
 
Slower powders give you more velocity in a longer barrel, but much of it burns outside the barrel with short barrels giving you less velocity and more muzzle flash. For short barrels use a faster powder like the factories do for short barreled ammo.
 
I have an old Speer reloading book (no. 7 I think). They developed loads for snubby .38's and found that the slower powders actually gave up more velocity, but with teriffic muzzle flash. Granted this was 40 years ago so take it with a grain of salt.
 
rcmodel said:
It doesn't matter.

Whatever powder in the manual gives the highest velocity in a long barrel will also give the highest velocity in a short barrel.

You don't pick powders based on barrel length.

You pick powders based on the one that gives the highest velocity, or best accuracy in the load manuals.
Depending on your needs.

rc
Click to expand...
This topic is one of the most misunderstood out there. RC set me straight a long time ago. Whether you use a fast or slow powder has very little to do with barrel length. It is 100% true that longer barrels almost always achieve higher velocities than shorter barrels (up to a certain length) but this fact is true regardless of the powder being used.

I tinkered with this for some time. I found that, when using fast powders such as Bullseye in a certain cartridge, there would be about a 200-300fps difference between a 5" and a 16" barrel. I was somewhat surprised that, when using slow powders like 2400 in that same cartridge, there was about a 200-300fps difference between those same 5" and 16" barrels.

Whether you use a slow or fast powder has more to do with the cartridge pressure and projectile weight than anything else and all of this will be provided by the published load data. If you will notice, most books list the load data starting with the fastest powders to the slowest. Some, like the Lyman 49th, will also have what they determined to be the most accurate load in bold... This doesn't mean it will be the best for you but it usually makes a good starting point.

Most of the fun I have had reloading is finding out what those sweet loads are. Contrary to popular belief, there is no one perfect load for any caliber. Each gun, bullet, case, powder, etc. will vary slightly making it up to the shooter to find what works best with his/her combination of variables.
 
rcmodel said:
It doesn't matter.

Whatever powder in the manual gives the highest velocity in a long barrel will also give the highest velocity in a short barrel.

You don't pick powders based on barrel length.

You pick powders based on the one that gives the highest velocity, or best accuracy in the load manuals.
Depending on your needs.

rc
Click to expand...
RN said:
@rc..Perfect...That's what I needed to know...
Click to expand...
Oh well, late to the party again and there's nothing left to do. I just love a happy ending! :D
 
Uniquedot said:
Slower powders give you more velocity in a longer barrel, but much of it burns outside the barrel with short barrels giving you less velocity and more muzzle flash. For short barrels use a faster powder like the factories do for short barreled ammo.
Click to expand...


Actually the majority of it still burns in the barrel. It's a misconception that a large amount of it is burning outside the barrel.

The only reason to use the faster powder is if you want less velocity or a lighter load.
 
Last edited:
Actually the majority of it still burns in the barrel. It's a misconception that a large amount of it is burning outside the barrel.
Click to expand...

True. With slower powders and short barrels, a lot of powder will still be burning after the bullet has left the barrel.
 
So maybe a little faster of a powder in a short sub compact g29? I ask because AA#5 gives me a little flash..Shoots nice though..
 
ljnowell said:
The majority of powder burns in the first inch or so of the barrel.

A lot of the powder isn't burning outside the barrel.
Click to expand...

I agree. A lot of powder is not burning outside the barrel. Most of the powder will burn (or at least, ignite) in the first inch or so of the barrel. And with some slower burning powders, combustion will not be complete before the bullet leaves a short barrel and the powder will still be burning after the bullet is gone.
 
if you are getting unburned powder out the barrel, there is something wrong with your load. a proper load will have complete powder burn well before the bullet leaves the barrel (even a short barrel).

a good example of a wrong load: a low pressure load of h-110. lots of unburned powder, misfires and/or hangfires. this is one reason why i follow reloading manual guidelines.

murf
 
Years ago I read a study on this stuff and it seems that volume has a lot to do with x powder and x amount of barrel length for proper combustion and complete burn. I have no idea about small bore handguns and can't even remember what lab did those tests as it was many years ago, but common sense tells me that if there is excessive muzzle flash then lots of that slower burning powder is burning outside the muzzle. And not achieving full potential. I'll stick to a slightly faster powder with less flash and get the most velocity without the blinding effects. Of course others will stick to what they KNOW. As far as loading manuals go and data from powder companies... I have gotten great info from them over the years simply by making a phone call. Sometimes your best info will come from them rather than what we think we know from what we have read on these forums.
 
murf said:
if you are getting unburned powder out the barrel, there is something wrong with your load. a proper load will have complete powder burn well before the bullet leaves the barrel (even a short barrel).

a good example of a wrong load: a low pressure load of h-110. lots of unburned powder, misfires and/or hangfires. this is one reason why i follow reloading manual guidelines.

murf
Click to expand...
Yes, if the optimum powder is selected for the load, you can get at least a 95% burn before bullet exit. But with powder availability what it is today, you may not be able to find the optimum powder and have to go with one that will work, but is less efficient leaving more powder unburnt when the bullet leaves the barrel.

For example, 5.5g Power Pistol in a .380ACP from a Ruger LCP will give me 950fps with a ~62% burn at bullet exit. 3.7g of N320 will give me 940fps with a ~98% burn. And 4.3g of N330 will give me 960fps with ~92% burn. But I can't find N330 or 320 and I have Power Pistol.
 
Uniquedot said:
Years ago I read a study on this stuff and it seems that volume has a lot to do with x powder and x amount of barrel length for proper combustion and complete burn. I have no idea about small bore handguns and can't even remember what lab did those tests as it was many years ago, but common sense tells me that if there is excessive muzzle flash then lots of that slower burning powder is burning outside the muzzle. And not achieving full potential. I'll stick to a slightly faster powder with less flash and get the most velocity without the blinding effects. Of course others will stick to what they KNOW. As far as loading manuals go and data from powder companies... I have gotten great info from them over the years simply by making a phone call. Sometimes your best info will come from them rather than what we think we know from what we have read on these forums.
Click to expand...


A big fireball isn't necessarily a sign that lots of powder is burning outside of the barrel. It's just a characteristic of a slow burning powder.

For example 2400 in a 2" barrel will throw a big fireball even though probably 95% of the powder ignited and burned in the barrel. The gases are still expanding and burning. When the hit the air outside the barrel the will make a nice fireball.

You will not however get any better performance by going to a faster powder.
 
For example 2400 in a 2" barrel will throw a big fireball even though probably 95% of the powder ignited and burned in the barrel.
Click to expand...

May I ask where you are getting that 95% number? Quickload calculates that in .44mag, only ~62% will burn before the bullet leaves the 2" barrel. After that, it really doesn't matter how much of the remaining powder burns or where. Increase the barrel length to 6" and you get an ~85% burn.
 
JRH6856 said:
May I ask where you are getting that 95% number? Quickload calculates that in .44mag, only ~62% will burn before the bullet leaves the 2" barrel. After that, it really doesn't matter how much of the remaining powder burns or where. Increase the barrel length to 6" and you get an ~85% burn.
Click to expand...


A number just pulled from nowhere.

The point I was trying to make is that the phrases "lots" or "most" are inaccurate. It also matter what caliber and load

It's a false belief that the big fireball from a snub is "most" of the powder and that a faster powder will give better performance. That's not the case. The slower powder will always give better performance(I guess there could be a rate situation where it won't, though I am yet to see it).

I also wouldn't accept quick load numbers as fact either.
 
JRH6856 said:
I don't. But I do accept them as a more accurate estimate than a number pulled from nowhere. ;)
Click to expand...


There are lots of opinions on the flash with slow burning powders and the percentage of powder burning in the chamber and the bore. There is also much debate on where the continuing burn takes place (does the powder continue burning down the bore it is it simply the gases?) in relation to the gases escaping.

I am in the camp that much of the muzzle flash seen cones from the burning gases exiting the barrel and being exposed to the oxygen in the air.

This thread makes for good reading:
http://thefiringline.com/forums/archive/index.php?t-527687.html
 
It seems to me that if magnum handgun powder were still burning in the barrel?
Like even way slower rifle powder.

Then revolvers would experience bore erosion from the burning powder.

But they don't!

Muzzle flash I'd caused by the supered heated gas from the already burned powder suddenly being expelled into the atmosphere, where free oxygen lights it up like gas plasma.

rc
 
rcmodel said:
It seems to me that if magnum handgun powder were still burning in the barrel?
Like even way slower rifle powder.

Then revolvers would experience bore erosion from the burning powder.

But they don't!

Muzzle flash I'd caused by the supered heated gas from the already burned powder suddenly being expelled into the atmosphere, where free oxygen lights it up like gas plasma.

rc
Click to expand...


That's my opinion too RC but it may be that we are in the minority.
 
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