I was shooting with someone yesterday and they had some 30-06 reloads some loaded for them.
The load was a 150 grain bullet over 48.5 grains of 4064.
He was having primers back out. I told him to stop shooting them but he shot about half a dozen and one eventually got stuck. Now my book shows it on the low end but none the less something was wrong. I have never seen this happen so any help you could give I would like to have to pass on to him plus to keep in the grey matter for future knowalage.

With a load producing rather moderate pressure, in a chamber with considerable headspace, this is what happens. The firing pin blow drives the cartridge forward, away from the bolt face. The explosion of the primer mix forces the primer cup back to the bolt face, causing it to protrude from the case head. The case wall grips the chamber, holding the case forward. If the pressure's high enough, the case will stretch back to the bolt face and push the primer back in. If it's not, the primer's still sticking out. That should be a very mild load. I'd check the headspace on the rifle and make sure it's within spec. Cases sized so the shoulder's pushed back too far would have the same effect.

Ricochet is right on in his explanation. You did not say what type of rifle was involved. If it was a push feed, the stuck case could have resulted from the shoulder dimension being so much shorter than the chamber size that the case was driven past the extractor and did not stretch back far enough to be caught by the extractor after firing.

Hard to say whether the problem is rifle or ammo related without measurements, but if the rifle worked normally with factory ammo (and primers appeared normal) I would suspect the reloaded ammo might be the problem. If, on the other hand, the factory ammo exhibited excessively flattened primers, this might indicate a head space issue with the rifle (due to the primers backing out on firing and then being flattened by the case as it stretches back to the bolt face).

Jim

There is also other logical explanations: Either the bullet weight or the powder weight may not have been what it was supposed to be... I have had my balance beam scale knocked off of zero, and then got some strange loads. perhaps things were not as they were supposed to be. magnum primers? next time your buddy should save some and do an autopsy on the disassembled loads... the point being: it is insane to keep shooting after warning signs, just to see if all the loads are too high pressure, after seeing two examples, I back off and regroup.

Could also be the brass was neck sized for a tighter chamber load in the other persons rifle. this would do a headspace thing. but it sounds more like pressure to me than headspace... also the necks could have been too long and jammed up the bullet release. no matter how light a load that can make for pressure spikes. also could have been too long into the lands as well...

Thanks guys. He has some of the rounds left. I will get them and pull the bullets and weigh the charges. To tell you the truth I didn't even look at what the rifle was. He got to the range before I did and had already been shooting it. When he showed me what it was doing I recomended he stop shooting. He shot on or two more and that is when it got the stuck case. Being the man is quite my elder I didn't argue when he wanted to try a couple more. I gave him my opinion and let it go from there.

I wondered about headspace issues but as I have never seen a rifle with improper headspace I was not sure.

Some good advice in the posts above.

How do the primers look ?
If they are still nicely rounded at the corners, but are pushed out of the case, it's a " sizing " issue. Not technically a pressure thing.

If they are flattened ( no corner radius ), or bigger at the rear than the front, then you have an indication of pressure being present. ( maybe a little more present than desirable ).

Look closely at the corner radius of the primer.

Travis F.

As more or less alluded to above, primers can "back out" when pressures are TOO LOW, as well as when they are too high! IF the primer pockets are still tight in these cases after firing, it is proof that the pressure was too low, since when they are too high, the first thing that happens even before primers start coming out is that the primer pockets expand and ruin the case!

Please explain how the primers will protrude whrn the pressure is "too high".
The protruding primers in this case are the rewsult of "headspace" and pressure
below around 40, 000 or so.
Take Care!

resizing the brass too far creating excessive headspace. When you push the shoulder back to far this happens. If it was a full load it would have stretched out full chamber size and possibly seperated.
David

Right! Primers don't "back out" when pressures are too high! They only fall out of stretched pockets when cases from excessive pressure ammo are extracted from the gun. They only back out when pressures are too low to keep the casehead flat against the face of the breechblock.

However, headspace can and often is increased in low-pressure loads by the force of the primer blast pushing the case forward in the chamber, reducing the head-to-shoulder length. This is one of the reasons that it is recommended, once you have used cases for reduced cast bullet loads, to only use them for such loads in the future.

Right on about the primers pushing the case forward. It seems that the case will stay forward until
around 40,000 psi. Then it comes back with full force once the brass yeilds.
I have played around with pressure sensing tape, and "OK Shooter" has done a finite element analysis
taht confirms this. If you oil the case it comes back at lower pressure, and the stretch
line is avoided.
Take Care!