Pressure vs. Recoil Impulse

[ContinentalOp]

There's an ammo issue I've been somewhat confused about so I hope someone here can maybe clear it up. I also hope that my somewhat convoluted posting is understood.

It's often recommended to avoid shooting +P ammo in alloy-framed guns that aren't rated for it. But is it really the pressure that's the problem or is it the amount of recoil energy generated?

For example, a common result of extensively shooting +P ammo in a non-+P rated alloy gun is frame stretch. Wouldn't such a condition result from the higher recoil energy generated by the +P ammo? It seems to me that the amount of pressure generated is largely contained within the the cylinder, which, as far as I know, is made of the same steel as steel-framed guns that are OK for shooting +P.

Yet, standard pressure Buffalo Bore ammo produces similar, if not more, recoil energy levels than equivalent +P loadings and are considered safe to use in such guns.

I guess what I'm asking is how does the pressure of the load have more of an impact on the gun's alloy frame than the recoil energy?

 

[Treeman]

The pressure acts equally in all directions. The cylinder walls contain it, the breech face(recoil shield in a revolver) contains it and the bullet moves relieving the pressure as it does so. Thus the pressures act upon the frame at the moment of firing since a portion of the frame is containing that pressure. Having said that, recoil undoubtably does contribute to wear and stress on various parts-especially the cylinder hand. Aside from the reports of frame stretching with higher pressure loads, component battering has generally been the issue of concern with stomper loads. I suspect that high performance rounds at "standard" pressures such as Buffalo Bore's are capable of creating the same problem over time............. But these types of damage require numerous recurring cycles to produce so occassional familiarization shooting and carry of such rounds will likey never manifest a problem.

 

[ContinentalOp]

That makes sense. Thanks for the info.

 

[walnutred]

I have also heard reports of frame cracks, usually on the bottom side of the frame where the barrel screws in. I wonder if these are caused by the bullet impacting the forcing cone.

 

[WR Moore]

I would expect that pressure is what would be termed the root cause. Not just peak pressure, but the time/pressure curve.

Cracks on the bottom of the thread boss are generally because the frame is thinnest there. K-frame barrels tend to crack there because there's a flat machined there for yoke clearance. Again, this is the thinnest point.