i've seen some pretty bad nail & hilti gun accidents. we use hilti guns at work to shoot nails into concrete decks to install acoustical ceilings. i've seen lots of riochets and even seen a co-worker...

went out to the garage to weld up a couple brackets. i forgot to turn the valve off on my mig gas last time i welded and the bottle is empty. i've only done that twice in the last 10 years, last time...