The .40 is certainly more intense, but then again most .40 autos have a much heavier recoil spring and a few (as I recall) have a more massive slide. AS noted by more than one person above you would have to WORK at it to wear out a modern semi-auto by shooting it. I remember reading some years back about a Glock 17 that had a million rounds thru it with zero breakage. I don't know if they have done that with a .40 or not. The NYPD test for approval was 10,000 rounds.