Powder is too fast? What??

[JackRydden224]

I'm having a a custom DI 9mm upper built and the builder said the following about using Winchester 231 as my reloading powder.

231 is too fast for the DI9. Burns up in 2-3" of brl travel. longshot, HS-6, unique, herco & true blue all burn in the 99% range in a 16" tube.

Now I have no clue exactly what he meant by that or what will happen if use my current loads. Anybody care to enlighten me?

[BrianRodela]

Your powder is made to burn up in a short distance and the powder will not have any pressure left to cycle the action. Powders for pistols are designed to work in conjunction with both the weight, size and material of the bullet and the barrel leingth to provide burn and pressure throughout the whole barrel with little to no excess. 231 rates in the top 1/5th of powders regarding burn rate. By chosing to use a slower burning powder, it will increase the chances of providing adequate pressure left to impinge on the Bolt Carrier Group and cycle the action. Hope this helps.

[JackRydden224]

Your powder is made to burn up in a short distance and the powder will not have any pressure left to cycle the action. Powders for pistols are designed to work in conjunction with both the weight, size and material of the bullet and the barrel leingth to provide burn and pressure throughout the whole barrel with little to no excess. 231 rates in the top 1/5th of powders regarding burn rate. By choosing to use a slower burning powder, it will increase the chances of providing adequate pressure left to impinge on the Bolt Carrier Group and cycle the action. Hope this helps.

This helps and it actually explains why people need to find the ammo that fit their gun. From what you said I gathered that I need different powder depending on my barrel length. Winchester 231 is fine when I shoot my reloads through my handgun (and probably something like a 7.5 inch AR pistol type weapon) but I would need something different for my long gun.

I guess I just need to get different powder and be more meticulous with my record keeping.

[Ferrum]

Brian is spot on...

It also takes a little patience getting the load correct. Most of the reload manuals have information for pistol loads and tend to over look longer barrel lengths.

[JackRydden224]

Brian is spot on...

It also takes a little patience getting the load correct. Most of the reload manuals have information for pistol loads and tend to over look longer barrel lengths.

Thanks for the excellent advice. Now I remember in my Lyman's manual there is a 9mm load that's based off of the Ruger PC 9 (I think, memory is a bit fuzzy) and I was wondering why they would use a 16" carbine to test the load.

Anyways, is there a recipe that's good for both carbine length and pistol? It'll be so much easier to have one load that fits all.

[XDRoX]

I've never seen a 16" barrel that won't shoot normal 9mm rounds. If someone is designing a 16" barreled rifle for 9mm then they better make sure it functions with normal 9mm ammo. Everyone can't be expected to custom load their ammo.

Of course you can custom tailor a round using a slower powder for a longer barrel but it shouldn't be required to get the rifle to function.

I've shot 9mm with much faster powder than 231 through my 16" carbine and have never had a problem.

It would be fun to see what kind of velocity you could get out of some slower powders in a longer barrel but isn't necessary for function IME.

[shooterbill]

Check your current loads when you get the new gun. If they don't work in the carbine, then try the slower powders. Longshot is great in 9mm.

[shooterbill]

Check your current loads when you get the new gun. If they don't work in the carbine, then try the slower powders. Longshot is great in 9mm.

[Kodemonkey]

Here is a handy chart on powder burn rates I came across. Might get you looking in the right direction. Notice where the 231 is vs. longshot.

http://www.lapua.com/upload/reloading/reloadingburningratechart2011.pdf

[J-cat]

I've never seen a 16" barrel that won't shoot normal 9mm rounds. If someone is designing a 16" barreled rifle for 9mm then they better make sure it functions with normal 9mm ammo. Everyone can't be expected to custom load their ammo.

Of course you can custom tailor a round using a slower powder for a longer barrel but it shouldn't be required to get the rifle to function.

I've shot 9mm with much faster powder than 231 through my 16" carbine and have never had a problem.

It would be fun to see what kind of velocity you could get out of some slower powders in a longer barrel but isn't necessary for function IME.

He's talking about a direct impingement gas operated mechanism, not a blowback action. You've never seen a blowback fail to operate a normal 9mm load and neither have I, but the OP's gun is a whole different animal.

[XDRoX]

Here is a handy chart on powder burn rates I came across. Might get you looking in the right direction. Notice where the 231 is vs. longshot.

http://www.lapua.com/upload/reloadin...echart2011.pdf

That's a cool chart but I question it's accuracy. Right off the bat I notice that it claims WST is faster than Bullseye. No way is that right.

But I do like the way they lay everything out.

[XDRoX]

He's talking about a direct impingement gas operated mechanism, not a blowback action. You've never seen a blowback fail to operate a normal 9mm load and neither have I, but the OP's gun is a whole different animal.

Oh I missed that.

I still bet he'll be able to get it to run with 231. If not I'm sure WSF, Unique, or a number of others will get him there.

[JackRydden224]

Thanks for the advice guys. A lot of good information.

If my current loads do not cycle then I'll trade some of my Winchester 231 for a slower burning powder. I learned quite a bit in this thread. The upper won't be done for another 16wks so I got some time to figure this out.

[JackRydden224]

Thanks for the advice guys. A lot of good information.

If my current loads do not cycle then I'll trade some of my Winchester 231 for a slower burning powder. I learned quite a bit in this thread. The upper won't be done for another 16wks so I got some time to figure this out.

[J-cat]

Get some AA#7 or some of that new Bullseye-86. I have a feeling it is the same stuff Federal uses in their AE line.