Remember Rule 1
If you are one of the many people who have an AR-15, you might want to review this safety reminder from Tod Jarrett and Rich Grassi.
"The AR (carbine) has a floating firing pin."
Dropping the bolt on a loaded magazine causes the firing pin to jump forward as the bolt slams home. Didn't know that?
"After you fired a few rounds, take the magazine out and clear the chamber. Check the round that came out of the chamber. The primer has a small dimple. The firing pin actually hit it."
For that reason, ALWAYS charge the AR15 with the muzzle pointed in a safe direction.
A properly maintained firearm with good ammunition will probably never accidentally fire when the bolt drops — but.... (you can fill in the rest.)
-fl