450Bushmaster.net

I'm new to the forum but I've looked at many of the crimping threads.

I'm loading the 250FTX with 37.0 Lil Gun. I've also tried 35.1. 2.225 COL with both Starline and Hornady brass.

Before the forum, I could not find crimp data. So, I went by a diagram that showed .480 and it cycled and functioned fine.

But, with the Hornady Black ammo - I could get 1" to 2" @ 100 Yds with a sandbag, 4x scope, 16" Bushmaster with Bowers suppressor.

My loads would hit the 1" target circle, then go 6" or more off in random directions. Usually high - but left or right. Finally, I measured the crimp on the factory and found it at .477 - then read in these forums suggestions of .473 to .475.

I only had a few projectiles to load some more at .477 and have not had a chance to test them yet.

My question is if anyone has tested grouping at various crimp measurements and if it made a difference. Am I an on the right track?

PS I've also used H110 and had the same issue - that's why I switched back to Lil Gun

http://450bushmaster.net/viewtopic.php?f=5&t=15405&p=53615#p53615

Hoot

Thanks, Hoot. Very helpful. I'll follow the suggestions.

So I might go ahead and go another .001-.002 on my crimp before I test them - say .475 or .476. The question is if you all think that will have much of an effect? I was curious on what your hypothesis would be.

I hope to try in in the next couple days. I only had about 10 projectiles left so I'm awaiting my next order. I'm going to try the 225FTX as well.

DARYLU wrote:So I might go ahead and go another .001-.002 on my crimp before I test them - say .475 or .476. The question is if you all think that will have much of an effect? I was curious on what your hypothesis would be.

I hope to try in in the next couple days. I only had about 10 projectiles left so I'm awaiting my next order. I'm going to try the 225FTX as well.

Well, it just sounded like you were getting two different POI that suggested different velocities. That is certainly not the only cause that could lead to what you experienced. I know from experience that vertical stringing can come from how tight or not, you hold the rifle. However I have never seen it amount to 6 inches. That almost speaks to hardware malfunction and that 6" road usually leads to a scope issue. You however have added a variable in the form of a suppressor to the equation. Try shooting without it on if you haven't already. There certainly could be an incidence of baffle swiping in the suppressor. If you can disassemble yours for cleaning, poke through the runoff for slivers of copper.

That having been said, there is only good that will come from having your rounds properly crimped. Don't change too many variables at once. Take the crimp down to .476 and retest. No point in squeezing the dickens out of your bullets or case mouth walls.

Hoot

Have you been using the "Tight Neck" method with the 45 Colt resizing die, Hoot?

Dan

dantheman wrote:Have you been using the "Tight Neck" method with the 45 Colt resizing die, Hoot?

Dan

No Dan. It was a good idea, just not a great idea. Too hard controlling the concentricity of the reduction, which is probably testimony to the fact that our cases are not the same hardness all the way around or possibly only after the first firing. Not sure why. Could be the gas leaking around them that anneals them a little. that's what sooting is.

Hoot