When is a high primer unsafe?

I loaded 500 rounds of 45 ACP and had one primer measure .0031 (31 thousands) higher than the case head, I realize I got distracted on that one round but would it have been safe to shoot? I disassembled it and moved on.

Just curious.

I bought a dillion case gauge and check every round I load...anal I know.

Red

Personally I just use my fingertip to make sure the primer is either level with the case or, preferably, slightly below level. I would not fire that case though the danger is minimal, yet very unnecessary.

I probably would have just seated it again. I don’t know how your seating them but if y hand primer goes full stroke and the primer is sticking up something is broken.

Dillion 650.

Any high primer increases your head space, so you would have a tight chambering or no chambering of the round. Sometimes, the firearm can seat it deeper upon chambering. But sometimes you can carefully reseat the primer of the loaded round. Proper seating depth of the primer is .003" to .008" deep. I try to put all primers at .004" deep.

0.0031 is 3 thou, not 31. Hard to even measure. 31 is really high and a problem.

[quote=ChadTRG42]Any high primer increases your head space, so you would have a tight chambering or no chambering of the round. Sometimes, the firearm can seat it deeper upon chambering. But sometimes you can carefully reseat the primer of the loaded round. Proper seating depth of the primer is .003" to .008" deep. I try to put all primers at .004" deep. [/quote

Increase headspace ? Please explain how .

A 45 ACP head spaces on the case mouth. If the primer is proud by .003", you just increased your head space by .003". The primer is forcing the round further forward in the chamber .003", and case mouth is that much closer to the end of the chamber in the barrel. The difference between min and max is (generally) .007", so you are almost half way there on max head space tolerance. (I don't know off the top of my head what the min/max length difference is on a 45 ACP, but most rifle chambers are .006" to .007") You could have a chambering issue from the proud primer.

That makes no sense . The case stops in the chamber at the case mouth . The rim in the chamber does not move forward . Headspace does not move .

I run a lot of rounds through a Dillon 650. If you get lazy on the down stroke you can end up with a high primer. Concentrate on a complete downstroke and the problem goes away most of the time.

It can cause doubles in a semi-auto. How high do they have to be to do so? I do not know.

Headspace is from bolt face to chamber end. On the brass its from case head to case rim ( or now the primer face to the rim). If the primer sticks out you effectively increased the case length since it wont sit flush with the bolt face. The issue is the headspace increases since the bolt wont be fully in battery if it sticks out enough and it does stop on the rim/chamber interface. Round might not fire, or fire out of battery, or possibly the case is driven forward by the force of the bolt and the case rim is squeezed into the throat causing an increase in pressure as the bullet wont release from the case as easy as it would otherwise.

Lots of knowledge here. Hope other reloaders are getting some benefit too.

Exactly!! The case is stopped by the case mouth, which is exactly what headspace is for this round. When you have a high primer that protrudes past flush of the case head (in other words, is sticking out), you have increased your head space of the round (not the chamber), and will cause the round to fit tighter into the chamber and can cause a problem.

^^ Good explanation also.

It's 45ACP, probably from 1911. It will HS on extractor most of the time. 3 thou is scotch tape thickness.

The primer will seat long before the case crimps . If the taller primer makes the case mouth just seat on the chamber ridge were it should [ just taking up the slack ] there is no way that raises pressure . Yes , messed up cases can not chamber sometimes . Most factory ammo is made to short for most chambers , then match handloads are made to exact chamber size . Both work fine . The original post said a high primer increases headspace , it DEcreases practical headspace [ the space from where the case fits the seating spot of the chamber to the bolt face ] for chambering . But other things can effect that , the extractor can hold the case to fire it [ you can get 40 S&W to fire in a 10mm Glock ] . Headspace's main function is to be large enough to let the cartridge fit in the chamber , but tight enough to set it off , there is a range . An exact fit to the chamber is zero headspace . When I chamber barrels I can set the headspace at whatever I want for a certain cartridge or application . That applies to standard factory ammo . If you handload you can make your ammo for your rifle for whatever headspace clearance you want .