I^^^^THIS 100% The Beretta 92, Sig 226, Glock 17, S&W 5906, etc. were all designed around the 9mm Parabellum. When the 40 S&W was shoe horned into those pistols, Beretta 96, Glock 22, S&W4006 etc and things started to break sooner. Most of the newer polymer striker fired pistols that were designed after the 40 S&W came out and designed specifically for the 40 S&W cartridge and then adapted to the 9mm hold up much better. The cartridge that is probably the toughest on pistol frames is the 10mm Auto, Glock designed their Model 20 around that cartridge and from what I here there are no breakage issues with it. From what I hear it runs like a sewing machine.
There is a lot of truth in this I believe. 40 got stuffed into guns/frames that were not originally designed to handle it long term. Later designs, say such as the M&P seem to handle 40 easily. It’s entirely likely that earlier designs may hold the pressure enough to be safe to fire, but show wear faster on some parts.
