[ZTC]

I've recent started reloading pistol ammo where all of my other reloading has been for bolt action rifles. I'm reloading 45acp and shooting it out of a m&p45, the issue is I've been cycling some rounds thru the gun manually and not firing just to see how there feeding and I've had a few that the after being cycled once the bullet is getting pushed down in the casing a little almost causing a compressed load. Ive bought some brass new some once fired and some has been given to me by folks at the range. I'm loading them with 5gr of unique with a 200gr fmj speer bullet. Ive checked each cartridge for proper length and wigth and checked every round for OAL and its all good. I also used a full length resizing die on all the rounds. Any info as to why its doing this?

 

[RevolverDan]

What kind of crimp are you using? I've been using Hornady's taper crimp as the last station after seating and haven't had that issue in my P220.

 

[oldguns]

Are you using a taper crimp die? Pretty much mandatory on .45 ACP. I like to see about half the thickness of the brass pressed into the bullet.

 

[Match10]

Your taper crimp is not compressed enough. Try a smidge more.

 

[galvatron]

What is your OAL.

Do these rounds cycle fine in another pistol?

 

[zetor]

That is something that is just inherent with a 45 acp. You probably aren't doing anything wrong. It is a large heavy bullet and is going to be more prone to being set back. The bullet has a lot more inertia than other common reloaded rounds. The larger the dia bullet becomes, the less the ratio between circumference:mass ratio (holding power) becomes. It head spaces off the mouth and needs a very slight taper crimp.

 

[ZTC]

Thanks guys it looks like its my crimp. I'm gonna do some playing around with it! Thanks again

 

[1str8shot]

its all in the crimps, its all in the crimps.....

 

[SongDogSniper]

That is something that is just inherent with a 45 acp. You probably aren't doing anything wrong. It is a large heavy bullet and is going to be more prone to being set back. The bullet has a lot more inertia than other common reloaded rounds. The larger the dia bullet becomes, the less the ratio between circumference:mass ratio (holding power) becomes. It head spaces off the mouth and needs a very slight taper crimp.

Keep in mind the good advice Zetor gives here. Sure give it a little more, but just don't overdo the taper crimp trying to prevent any set back under all circumstances (like multiple re-chambering of the same round over a long period). Same applies to any similar cartridge that head spaces off the case mouth, don't over do the crimp.