December 7, 2012, 04:09 AM
Anyone here use the Winchester Auto Comp powder in 9mm, 40 S&W, or 38 Special, 357 mag loads? Just wondering how it compares with other powders and is it clean burning "in your opinion"?
December 7, 2012, 05:07 AM
AutoComp was developed for use in compensated semi-auto pistols. It's very low flash and it's clean to aid in allowing shooters in competition to finish the match without fouling the pistol.
As for revolver rounds like the 38/357, I'm sorry I have no idea. It's reported to work well in the 9mm, 40 S&W and 45 Auto and I guess if you can give it a try in the 38/357 and see. AutoComp is on the slow side like HS-6 so you might not want to use it for standard pressure .38 Special loads but that's only a guess. sorry i have no first hand knowledge but because of how it was marketed I didn't think i needed to give it a try, especially since I'm so happy with W231, HS-6 and W296...
December 7, 2012, 06:00 AM
It's definitely on the slow side. But unlike most slower powders, it doesn't come with the heavy charge weights. (The charge weights for Auto Comp are similar to Unique in the big 3 semiauto rounds).
I was a bit skeptical with the published information, figuring it was on the conservative side. And I think in 9mm, it might be. But let's just say I found the limits of my 40SW Glock without going over the max charge. So the notable difference in charge weights compared to, say, the very similar HS-6 seem to be for real. I don't have a chrono, but I've seen other peoples' chrono results, and they look pretty good compared with Hodgdon's info.
It appears you get the higher velocity (and the higher recoil, unfortunately) of a slower pistol powder with the same charge weights of a medium powder, very little flash (just a tiny bluish flame), it meters as well as HP-38, and it burns clean when used, appropriately.
On paper, it should be better for 40SW and hot 9mm than for 45ACP, but I've used plenty of it with cast 45ACP and 9mm loads with no problem. I've also used it in 380 (Winchester uses this powder in some of their factory 380 loads) and 9mm mak, but haven't tried it in 357, yet. The powder is so dense it would disappear in a 357 case.
I've read where some people think it's WSF with a flash suppressant added.
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