Help - Cratered Primers

[ijt101]

Just recently started reloading 45 acp with my dillon and am expetriencing some cratering of my primers after firing. About 50% of the brass appear to be this way while the remainder look normal.

Am loading 230 grain fmj into range brass using 4.0 grain of bullseye and federal 150 primers which would be a mild load.

Now - I was shooting multiple guns, (2 1911 and 2 tommy guns) and the tommys do have a heavy spring, but have never seen a primer look like this after firing.

I am trying to make sure I didnt F something up in my reloading process but cant figure this one out.

Anyone seen this before

[tabasco_joe]

It's not from too high pressure. As you approach maximum load the primer will swage out and fill out the rounded edge. With range brass you may have some with different primer hole sizes and case capacity. So they may have different pressures. But that isn't close to a maximum. Maximum pressure will swage out and even show tool marks from the bolt face. (Wish I had a picture handy.)

Adding a link that might prove informative.
http://www.realguns.com/archives/023.htm

[red dog]

never seen a pistol with a firing pin profile that large. are you sure that this is not the brass used in the thompson. i also agree that it is not your typical over pressure signature. leave the thompson at home and use this load in your handgun and see what the results are.

[WVBob]

Were the tommy guns being fired on full auto? A very hard primer hit in full auto could do that. I'm with Red Dog on this, check the primers after shooting the 1911's. I'ed almost bet they will look normal.

[ijt101]

Thanks for the feedback. I'm still somewhat new to reloading and try to keep an eye on my brass to make sure I don't have an issue and wanted to try and get some feedback before I made too many more.

The tommys I was shooting were both semi and we some of the new auto ordinance models and this one one of those rare occasions where I didn't have any issues with them.

I'll take my 1911 to the range this weekend and make sure.

[mpugachow]

I got some brass off of a buddy of mine that was shot out of a tommy gun and it looked exactly the same and it was factory loaded ammo so i would say it was from the tommy gun that you have

[aggitator]

Check your primer set on some unfired reloads if you didn't shoot them all. Could be the primers are not fully seated.