Please consider this: the Martini Cadet barrel shank is 0.750" nominal OD and is considered to be perfectly safe with 30-30s and even 44 Magnums. So why would not a small-shank high wall (with a barrel shank considerably larger than the Cadet) be considered safe with the same loads?
Answer: the high wall is safer because of the larger shank, but it's necessary to use a barrel made of modern steel to take advantage of that extra strength. The blown-up high wall shown above had a failure mode that began with the barrel split at the 6:00 position; this failure of the hoop strength support then caused the receiver ring swelling that resulted in the top of the ring blowing off. If a barrel of modern steel had been used then it's barely possible that the ring would have been OK, much like the receivers that Buhmiller failed to blow up. I'm no physicist (or even a good mathematician any more) but I do know that the barrel shank hoop strength component is crucial to the action's ultimate yield limit. Most good gunsmiths have been trained to not cut their barrel threads to an oversize force fit, so that when the barrel shank swells/heats when fired then it doesn't crack the ring. There must be enough hoop strength and clearance in the threads to prevent this radial pressure from expanding the receiver ring beyond its limit, and obviously the old high wall barrel was too weak.
Regards, Joe
