Strange primer event

AL45

New member
I replaced the factory spring in my Ruger Redhawk .45 Colt with a lighter spring. I wanted to make sure the spring would deliver the proper primer strike, but rather than heading to the range with live ammo, I simply primed a few empty cases and headed to the garage. Upon pulling the trigger in both single action and double action mode, the primer would fire, but it would back out enough to lock down the cylinder making it hard to open. This gun has worked flawlessly with live ammo and the factory spring. What is the explanation for this?
 
When you fire a live round, the powder propels the brass back against the frame which would prevent what you have described from happening.

I wouldn't worry about it.
 
disseminator, that certainly makes sense. So the primer is essentially reseated when firing a live round. Thanks.
 
Well, there is surely a more thorough way to describe it but basically yeah. Pressure etc...

I have observed a similar effect when firing foam bullets from my 45 Colt, though it didn't jam up the cylinder for me.
 
When firing wax bullets, I drilled out the flash hole to stop primer set back. It worked fine.

David

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Yep as David R states. You need to increase the primer hole size (1/8" drill bit) to shoot primer only loads (wax). Otherwise the primer will back out on you. But you must keep your cases separate if you do this. The low pressure (but high enough to move the primer) is why it does this. Shoot a wax bullet and you'll be surprised actually how much pressure a primer actually produces. BTW, I used .38 cases when shooting wax 'back when' for basement shooting. .357 cases were used for normal loads.
 
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Primers back out during firing because their brisance (suddenness of explosion) is high enough to drive the primer cup back faster than their gas can escape through the flash hole to relieve the pressure. This is the reason drilling the flash hole out prevents it from occurring. You can also make a load with light bullets and too little powder that doesn't sustain pressure high enough for long enough to drive the case head back enough to reseat the primer.
 
Now wait!
According to a recent thread, it's the front of the case selling in the chamber 'Sticking' the case to the chamber and chamber pressure backing the primer out...

No kidding now, that was what they wrote...
Now you have the primer back out in a straight wall case, no bullet or powder, open bore in .45 and the story changes...

Redhawk firing pin retracts after strike, this is probably allowing the primer to back out.
The flash hole simply isn't big enough to relieve pressure from detonation fast enough.
With the powder burning, and the bullet effectively plugging the barrel, the case would normally move backward reseating the primer before ejection.
Lots of pressure when that bullet plugs the barrel for a millisecond, the case moves backwards and reseats the primer.

Or that's the way I see it...
 
The primer always back out, Jeep. Sorry but that was part of the “other” thread too... but in this scenario the rest of the process that ordinarily reseats it is missing. There’s nothing happening but a primer. What pushes the primer back against the breach is it’s own ignition, not the pressure from the powder charge. Now, the main charge pressure will certainly do other things to the primer, like cratering, mushrooming, etc, but it’s not responsible for the initial movement.

Your last paragraph is essentially correct. I don’t recall any (knowledgeable) folks in that other thread claiming that what initially unseats the primer is chamber pressure.
 
you'll be surporised:

The low pressure (but high enough to move the primer) is why it does this. Shoot a wax bullet and you'll be surprised actually how much pressure a primer actually produces

Not me, I have helped reloaders drive bullets out of the throat of the barrel and back into the case to facilitate opening the cylinder, rotating the cylinder and or pulling the trigger. And then there is the primer dent. Pressure has to come from somewhere to get the dent to facilitate the primer conforming to the firing pin. And then there is that part that is not discussed among knowledgeable reloaders;) , hammer bounce.

F. Guffey
 
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