The other day, I was working up a load for my buddy's .243. I was working with a 95 gr. Nosler Ballistic Tip on top of Varget powder. We used the brass he had after firing several boxes of factory ammo. Most of his factory brass was Federal, but some was PMC and Winchester.

The load was 33.5 gr. Varget, which is 1.5 gr. under max. I seated the bullet out to the lands and then about .050 deeper. Accuracy was excellent. However, the primers on this load pushed out from the primer pocket about 1/32 or 1/16". It seemed to do this only in the Federal brass. There were no signs of excessive pressure. No cratering, no difficult ejection of the case. If it weren't a new rifle (brand new Remington 700 VLS) I would maybe suspect a bolt problem. The only thing that makes me wonder is the fact that the primers pushed in very easily.

Does any have an idea?

I find that federal brass already has loose pockets compared to the other manufactures. But never had a issue like you. Have you tried seating any more primers? If they are loose, then that brass has had it.

Back the bullet up a little....seat it a hair deeper....just a thought... But i dunno sounds like a pressure prob somewhere in the system, good luck getting it straightened out!!!

mias, any idea how far the headspace is for those federal cartridges after you resized them. also, did you full lenght resize or neck size?

Probably a loose primer pocket, just goes to show the differences in manufacturing specs. What primers were you using, the cup metal on the Federal primers tend to be a little softer than that of speer or ww.

Since you looked for other signs of excessive pressure and found none, since the primers pushed in very easily, and since the primers only backed out of the Federal brass, I believe that you fell into a batch of soft brass (or brass with oversized primer pockets.)

A bad lot of brass is not unheard of. I had a box of 20 Remington 8x57 170 grain factory loads that I bought in 1981 or so. They were stored indoors under favorable conditions. When I bought a new Remington 700 CLassic 8x57 last year, I took these, plus a brand new box of the same cartridge purchased in November 2005, to the range to sight in. The 1981 lot was an unmitigated disaster. Out of 20 rounds, 12 rounds resulted in split case necks and accuracy on all of them was for poop. [:'(]The 2004 ammo was fine, and the new lot of Remington 8x57 brass I bought is also fine. I shoot ammo in milsurp guns that is from WWII with no problems such as this, so it is not the age of the cases, but the particular lot of brass, that is at fault.

This stuff would discard that batch of Federal cases and keep on going. It sounds to me like you know what you are doing in terms of looking for signs of excessive pressure.

Good luck!

If the primers are backing out past the head of the case, then it's probably a headspace issue combined with the soft/oversized primer pockets that has allowed the primers to back out that much. If the headspace were correct the primer wouldn't have room to back out that far because the bolt face would be in the way holding it in. What I've noticed from cases if handloaded that had their primers seat a little too easily (a sign that they are at the end of their useful life) is that these primers would flatten out flush with the case head on firing while the cases with identical charges with good pockets wouldn't back out at all. This is why I use a hand priming tool and pay close attention to the amount of pressure needed to seat the primer. If it's a little too light, I mark the case head with an "X" with a black magic marker so that I know to toss that brass after it is fired one last time.

Mike

And the winner is Driftrider

Yea, I believe drift is right. But don't rule out the dies. I have seen more than one time where the FL dies is pushing the shoulder way back where it should compared to factory ammo. Mossyoak is going thru this now.

Try partial resizing without touching the shoulder of the case, that will eliminate a headspace problem. However, I don't believe that is the trouble to begin with. A case that doesn't reach the shoulder of the chamber will allow the primer to back out, but then will press it back in when the case elongates under the pressure of the expanding gas. That will tend to flatten the primer, sometimes completely overfilling the primer pocket. I'd bet on soft brass or loose pockets first.