Pot belly brass

[evan price]

I've seen "glocked" .40 brass before and it's never been a problem for me.

I have a Sig P220 in .45 and I have been loading 4.7 grains Titegroup under 230-grain lead round-nose with Win LP in range brass.

I have noticed the brass gets a blackened area and a bulge very similar to "glocked" .40 brass. It didn't bother me so I ignored it.

I tried a heavier load this morning, 5.1 grains Titegroup, 230-gr lead round nose, Win LP, range brass. Felt heavier, shot well. Oddly, the brass did not have a bulge anymore. I have not done anything to the pistol or the brass, and it's mixed HS brass, all of them bulged at 4.7 but none bulged at 5.1. This is over Hodgdon's max load for this combination but had no pressure signs except for the absence of a bulge.

Any ideas?

 

[ReloaderFred]

It's hard to say without actually seeing the bulge you're talking about. Since you mention gas blow by with the lighter load, my guess is the heavier load is allowing the case to expand enough to completely seal the chamber.

You might measure the area that's bulged on the lighter load, and then compare it with the entire case on the heavier load and see if they're the same.

I didn't look up your load to see where it is with published data, but in some other calibers I've found the published maximum load to be a bit light in my guns. I've worked up several loads that don't match published data, with no excess expansion or primer signs, which aren't the best indicators anyway. Since all chambers differ, and there are variances in bullets, brass, etc., some loads work out differently in different firearms. I'm not recommending that everyone go over published loads, only pointing out some differences.

Hope this helps.

Fred