Some rifles function a little different, especialy older ones and with the soft primers of many commercial hunting rounds, theres a higher chance of an AD. HOWEVER, in MOST of those cases, I would bet hard money that some dude was fucking around with the gun and it discharged, then later said "I dunno, Bob, the thing just went off." Can it happen? Absolutley. Is it likley or common? No. Is it worth being scared of in a modern pistol to NOT have a round chambered when you NEEEEED it? Fuck no!