In the late 1980’s, Sig P226’s had a habit of cracking frame rails.
The Secret Service tested 12 of them in about 1987, 9 of these 12 cracked one or both frame rails during this testing. My recollection is that some failures occurred as early as 3000 rounds.
Royal Canadian Mounted Police SWAT adopted P226’s at about the same time and also had problems. However, these may have been broken draw bars and return springs, instead of cracked frames - I just don't remember for sure. I have no idea what ammo was used by either the USSS or RCMP.
Also at about the same time, the FBI concluded that any aluminum frame semi-auto would start having failures after about 10,000 rounds (which is one of the reasons they went with the ill-fated steel framed S&W 1076).
Sig modified the P226, which postponed, but didn’t completely solve, the problem.
The Secret Service later adopted the P228 and fired extensive amounts of Remington +P+ 115 grain 9MM’s through them. They did not have frame rail cracking problems. However, they did have a lot of miscellaneous parts breakage and accelerated wear. (They have recently gone to the P229 in .357 Sig.)
In other words, if you drive your car slow it will last longer than if you constantly push it to the limit. No surprise here.