Read, "Gunwriter who didn't get to keep his test gun..."
.40 cals do experience more KBs, anecdotally. Glock does not cut match chambers, so they do leave around 1.5mm more free space at the base of the cartridge. Because of the .40 cal's higher pressure, the case is more likely to blow than a 9mm or .45. KB's happen in all firearms, generally related to bad cases, hot loads, or squibs.
Make a concerted effort to keep your ammo seperate (or consolidate on one caliber). If you had a low-end spec 9mm case fed into a high-end .40 cal chamber, a clearance drill could hammer it into the bore far enough for the next round to seat- a world of hurt for somebody...
