Military term, when a weapon discharges unintentially.
There are different types of slamfire, the most scary one is while loading and cocking the weapon, this could be due to a faulty trigger group which allows the hammer to be released along with the bolt carrier folowing right behind as though the trigger was pulled, or because of a free floating firing pin which carries forward with inertia, with heavy milspec firing pins and lame civilian ammunition the primers could be detonated just by this inertia.
Another type of slamfire known as doubling can be caused in the same way, this is when two rounds are fired instead of one. Sometimes this can be even worse and your whole magazine can be unloaded.
Several civilian shooters have been killed when a fully automatic weapon has been loaded with commercial ammunition and has unintentionlly fired when loading.
Inertia problems can be fixed by using real military ammunition instead of civilian or by switching to a lighter firing pin. Faulty trigger groups are a serious but rare problem and should be fixed by an armourer ASAP
"I was holding the Colt M1991A1 loosly and pointed off to my 10 o'clock as I inserted the fresh magazine, but when I released the slide to chamber teh first round the weapon slamfired, surprising me and taking a chunk out of the wall to my left, if someone had been standing there with me they could've been killed"
Unintentional discharge of a firearm that occurs as a result of an impact releasing the weapons firing pin and potentially firing loaded ammunition. This condition can occur as a result of parts wear, or more commonly a manufacturers defect such as having a 'free-floating' firing pin. Typically solved by adding a spring to the firing pin or incorporating a firing pin block.
When Jim dropped his old SKS rifle from his truck, the slamfire almost killed him.