Over-Pressure from Old Primers?

[JB2000]

I just bought the dies to start reloading .45 LC and was going to use some old Winchester large pistol primers I've had for probably 20 years. I loaded a few primers into resized once-fired Starline cases from HSM cowboy loads. I placed one primed case in my Uberti and set it off. It fired just fine but the cylinder wouldn't rotate. Finally got it worked around to the loading gate and the primer had obvious pressure signs. I have heard of pressure issues with old powder but never thought an old primer in an empty case could show pressure signs like that.

Could it be something with the cases?

Thanks.

[bigedp51]

All primers will back out of the primer pocket and as the pressure builds higher the case is pushed back and contact the frame or bolt face.

Check the fired case and measure how far the primer is protruding.

My guess is the primer backed out as far as it could move, contacted the frame and prevented cylinder rotation.

Below a antimated image of a British .303 cartridge being fired. Watch the primer back out and then be reseated as the chamber pressure pushes the case back into the bolt face.

https://i.imgur.com/sHgqVJR.gif

Below a primer will back out the amount of head clearance it has, meaning the air space between the rear of the case and the bolt face or frame.

Your primer backed out as far as it could move causing the cylinder to bind. If you put some powder and a bullet in the case the primer will be reseated by the chamber pressure.

https://i.imgur.com/HK76WCp.jpg

[TomMcC]

Pretty much this, and that's about all there is to it.

By the way...cool diagrams and animation.

[JB2000]

Thanks very much a especially for the excellent animations! I was worried about using these primers. I’ll go ahead and get some loads put together.

[TomMcC]

Thanks very much a especially for the excellent animations! I was worried about using these primers. I’ll go ahead and get some loads put together.

When you capped off the primers, did you happen to see any flame coming out of the barrel?

[bigedp51]

Thanks very much a especially for the excellent animations! I was worried about using these primers. I’ll go ahead and get some loads put together.

My Winchester 30-30 at 38,000 cup or 42,000 psi always have the fired primers protruding. The chamber pressure of the 30-30 is not high enough to push the case to the rear and contact the bolt face.

Below if I put too much wet Mesquite in my S&W the steaks back out and look for another grill. :jester:

https://i.imgur.com/tJfBvwM.jpg

[JB2000]

No, no fire but I wasn’t watching very closely. It’s a 5.5” barrel and I had it pointing into a box with a rag in it to absorb the noise. If there was much fire I think I would have seen it.

[markm]

You're wasting primers. It takes quite a bit to make a primer inert. The retards on Arfcom posted a bunch of idiotic attempts years back...

[DG23]

You're wasting primers. It takes quite a bit to make a primer inert. The retards on Arfcom posted a bunch of idiotic attempts years back...

Show me ANY site with no retards and I'll buy you a beer.

[jsbhike]

All primers will back out of the primer pocket and as the pressure builds higher the case is pushed back and contact the frame or bolt face.


Speer used to have(and may still) instructions on their plastic bullets(no powder, primer only) that if used with standard brass to enlarge the flash hole to a certain drill bit size(& mark to not use with full power loads) to prevent the primers from backing out.

[Bimmer]

I loaded a few primers into resized once-fired Starline cases from HSM cowboy loads. I placed one primed case in my Uberti and set it off...


Speer used to have(and may still) instructions on their plastic bullets(no powder, primer only) that if used with standard brass to enlarge the flash hole to a certain drill bit size(& mark to not use with full power loads) to prevent the primers from backing out.

This... I did this with .40 cases to make blanks so I could test for light primer strikes in my S&W 610 as I fiddled with spring rates.

On the advice of the revolver guys, I bored out the primer holes to 1/8".

FWIW, a small pistol primer throws a real big flash in a dimly lit garage!