As previous members have posted, this is kind of an open question, with each make and model of semi auto having it's own characteristics. In my experience with 30+ autoloaders in the collection, I can't say I have ever had one fire out of battery. I shoot lead boolits almost exclusively, so there have been plenty of opportunities for a boolit that was cast a bit large to stick the action just short of locking in. Occasionally this happens. Sometimes the hammer falls, most of the time it doesn't.
I guess this would represent two conditions:
1 When the hammer doesn't fall, the disconnector had not re-engaged, preventing the trigger to release the sear.
2 When the hammer does fall, the disconnector is re-engaged, and the hammer does fall, but the slide isn't far enough forward for the hammer to hit the firing pin, or the firing pin block to fully retracted, or the striker (in the case of striker fired pistols) to engage the primer. I have never had a round fire without the slide locked in either condition.
I did have one kaboom (KB). I was shooting a mauser C-96 firing 9mm Parabellum with lead boolits. The square shaped bolt corner hit the primer as the lead boolit caught on a part of the barrel feed, and burst the cartridge. No damage was done to the gun, however, this did lead to using a different boolit design which fed better.
Some semi autos are prone to kabooms. This occurs when the feed ramp extends too far into the mouth of the barrel (a design flaw in my opinion). When the feed ramp extends beyond the solid part of the casing (0.200" from the head), the case may burst when fired, usually resulting in pretty severe gun damage and sometimes injuries to the shooter. Some guns are more prone, most have fully supported chambers and are not prone to KB's. With a bit of experience, you can tell which guns are throated too far into the chamber.