Pistol case head separation

[PAPA BEAR]

I have been loading for 30 plus years, have had that happen in rifle cases but never in a pistol case. They always split down the side before they seperate from the head. I over loaded a 38 revolver once, cracked the cylinder and the caseing was swelled and split down the side.

 

[joe-nwt]

Interesting.. Would you agree though that these aren't examples of "classic" case head separation like one would see in bottleneck cases and are likely due, like joe said, to a lack of robustness or other possible flaw?

I'm just trying to wrap my brain around the physics of it all I guess...

That's precisely the distinction I'm trying to make here. Defective brass or out-of-spec chambers will always cause problems, that's just part of the game. I think you and I agree, though, that there's no reason for a safely-loaded, structurally sound piece of brass fired in a well-designed chamber to separate at the head, even after multiple loadings.

I looked at those pictures on the other thread. IMHO, that type of cracking is cause by nothing other than work hardening of the brass coupled with an inherent weak spot caused by that "crimp" line in the case. I've never really measured the relationship between the bullet depth and the position of that line, I just always assumed it was a type of stab crimp for some really long/heavy bullet that they might offer in their lineup. I would think that all their brass for the factory-loaded ammo would have that line, not likely that they would have two different styles of brass. And lets not forget, it is not the manufacturers intent that you reload their factory ammo, it's a bonus. Winchester sells component brass that does not have that line IIRC.

In the end, a split from that line is relatively harmless. And if a true separation did occur in a revolver, I'm not so sure that would pose any danger to the shooter or the gun either. Pressure for the most part is quite a bit less than your average bottle-neck cartridge. Gas out the front cylinder gap or gas out the rear, I think the only possibility for significant damage would be to the extractor star. Not even sure if the shooters hand would be in the line of fire with a proper grip on the gun. In a semi-auto, the bullet is gone and there is already a large "vent" for gases before the slide starts to extract so I'm not sure there would be much damage there either. I don't think there would be as much damage as there might be from an overpressure round that caused a burst on a smaller unsupported part of the case.

All this is pure speculation on my part, just adding my 2¢.