Tight primer pocket

[Jasonaspears]

This is what I would really want to figure out. They all got tighter, not just a few

That's an issue I've never run into. And this was with brand new Lapua brass after firing? Now I'm puzzled

[hermosabeach]

Winner

How does a primer pocket get tighter after one firing?

OP
Can you post pics of the primers? Are you over pressure with a mil spec case that is thicker and has less internal volume?

Did you change brand or lot # of primers?

[J-cat]

He's saying his Lapua commercial brass somehow constricted it's primer pockets after the first firing.

[rd2play]

Yes, brand new Lapua, just one firing. I can post pictures, but there's absolutely nothing to see; it all looks normal. No over pressure signs. I'm very careful about that. I used the same box of primers.

This only happens with the new Lapua. All my other cases, Nosler and many unidentified ones work just fine, same primer, load and bullet.


I got the CH4D swage kit and it works fine on my Lee Classic. Not much to say about it... you put it in there, adjust how much you want to swage and start doing it.

[firebert]

Just don't adjust it to get too much swage or else you'll mushroom the rim. Not a big deal with junk brass but I'd kick myself if it was nice Lapua brass.

[Wrangler John]

Wild guess: It's like a compression fitting for copper tubing, firing pressure drove the case head back and compressed the primer pocket, rendering it smaller internally. I used one lot of Lapua Brass in .22-250 that drove me nuts. There were a few primer pockets that would not uniform with the Sinclair uniformer. It just wouldn't reach more than half-way down the primer pocket before jamming. All I could see was that the reamer was trying to drift off to one side, the pocket had a curve in it. Never had any other brass do that. If your brass had a slight defect like out of round or curved pockets that could tighten them up on firing. Another hassle was that after firing quite a few cases wouldn't chamber, same load, no excessive pressure, they just acted as if the headspace was too long. I measured every dimension, checked them for headspace against ones that chambered, couldn't find a difference. May have been the case body was deformed some way that caused them to curve like a banana. Just wasn't worth fighting with them so in the recycle barrel they went.

Had a few similar problems with some 6.5 -284 Lapua brass also. Now when I want premium brass I use Nosler.