[AGE]

Guys,

I am not a metalurgist, but I am a mechanical engineer. Some materials (like concrete, glass, etc.) are brittle and fail or break without a lot of distortion or stretching. Other materials are ductile and distort a lot (like copper) before breaking. Steel, as Wes has said, was not well understood 90 years ago. A lot more is known today and the various alloys in use generally behave much better in service.

Steel is known to become brittle at lower temperatures and there is actually a transition temperature where the behavior changes. Sometimes the transition temperature is perhaps 30-50 degrees F. Also the hardness that many people like to brag about makes a steel more brittle.

The rough surfaces in the C-96 bolt failure look like some sort of brittle failure to me (but the picture shown above doesn't really allow one to make an official conclusion). Fatigue failures can look like brittle failures with little deformation, but this usually requires over 100,000 cycles--not likely in a semi-auto firearm.

The C-96 bolt failure looks to me like the result of using poor steel, perhaps on a cool day (but who knows?). Herb, did this failure happen in Utah in the winter?

Fortunately my S&W is only a few years old and, hopefully, uses modern steel. The barrel looks like stainless steel which is usually very ductile without transition to brittle behavior at any likely service temperature.

Also, the Russian ammo seems suspect and any gun, new or old, poor or excellent, is more likely to fail if subjected to excessive pressures.

Another fly in the ointment is the fact that the Russian ammo uses steel cases rather than copper alloy used in domestic ammo. I don't know why that might change things, but again, who knows?