Can someone please explain this?

M

mako8551

New member
Is it normal when shooting primed cases out of a a revolver to have your primers back out substantially?? If so why does the lack of power and lack of bullet cause this?

Lightening up my mainspring tension screw (for IRC) and testing function on primers only. So just running through 50 primed UNLOADED cases to test function.

Shot 6 rounds and it started to jam. On inspection the primers had backed out far enough to jam the cylinder. This was repeated 16 more times. Same result.

Checked primers and brass from last fully loaded rounds and they had not backed out at all. Same primers and brass,fired from same SW 627. Only thing that changed was mainspring tension screw.


So this just happened, can anyone tell me why going off of past experience??
 
When the gun is fired the primer backs out some from pressure. When the case head slams back into the recoil shield it reseats it. A low power round doesn't have the power to reseat it.
 
Hawg has it right - this is exactly what's going on.

If the primer strikes look "cratered" at the edges, that's your over-pressure sign (along with sticky extraction).
 
I used to make wax bullets. Get a cake of parrafin about 1/2-3/4" thick. Take primed cases and push them through like a cookie cutter. Revolvers jammed constantly, always the primer stuck against the recoil shield.

I think Bill Jordans book "No Second Place Winner" described how to ream the flash holes in the cases to alleviate that problem. I did and they worked perfectly. He also mentioned marking those cases so you don't accidently load them with full power loads because of a potential pressure spike.

Thats how I learned about that...
 
backed out primers

HAWG, Thanks for the simple explanation of backed out primers. It makes perfect sense to me, not like some explanations in reloading manuals. I was always under the impression it was TOO MUCH PRESSURE!
 
"1) Is it normal when shooting primed cases out of a a revolver to have your primers back out substantially??

2) If so why does the lack of power and lack of bullet cause this?"

1) Yes

2) Yes

Snake
 
Unlike other action types (single shot, semi, etc.) with a revolver, there is no steel (breechface) tight against the base of the case when fired. Since there is room for it to move (if there wasn't a little room, the cylinder would bind easily), and it is lightest, the primer back out until it hits the recoil shield. With a bullet (even a wax one) in the case, there is enough pressure to move the case itself back, reseating the primer.

The fired case (slightly backed out) simply slides along the recoil shield as the cylinder turns for the next shot. Often movement of the revolver as it is handled to unload hides the fact that the cases have backed out of the chamber slightly (and sometimes, the slip back in all the way), so we seldom notice this has happened.

With no bullet (or wad, as in a blank) at all in the case, there is often enough pressure to unseat the primer, but not enough to move the case, so the "high" fired primers drag, and tend to tie up the gun.
 
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