Well, I guess I'll chime in here with a personal experience.
My shooting partner used to compete in IPSC back in the late eighties with a S&W 4516. This is a 3" barrel 45acp. In order to make "major" we had to load his ammo with a 265 grain keith type cast wad cutter and max charge. He got smart and sold the smith and bought a Glock 17 and I was left with a bunch of 265gr. 45 auto ammo. Well, I had my Glock 21 and decided to just use it as a noisy bullet puller.
One night at the indoor range, I had a guy on each side of me shooting 357 revolvers with short barrels. The 265gr ammo would sometimes not feed and the slide would close on an empty chamber. Sure enough, I had a ftf and assumed the empty chamber situation and without thinking (and stupidly) jacked the slide and fired again. What had happened was the first failure was a round without powder which moved the slug down the barrel about an inch. The second round went off and I got one hell of a kick and two slugs hit the target downrange the prinmer was completely flattened on the fired case, there was a small smiley face at six o'clock and I had a very slight ring bulge in the barrel. That was it, I continued to use that barrel in that gun for another match and then sent it in to Smyrna for a new barrel. As I recall the load we were using was 5.5 grains of red dot. If ever an overload/overpressure was going to cause a KB that was a great opportunity. As it happened, no real harm or damage and I gained a great deal of respect for my 21.
Marty in Oregon