Defective firing pin mod 100 Winchester smi auto?

Answer 1

Sometime in the late 1970s or early 1980s, it was discovered that the firing pins in some Win. Model 100 rifles and carbines broke inside the bolt. This could result in the front part of the firing pin protruding from the bolt which resulted in the rifle firing as a full auto when subsequent rounds were chambered (a "slam fire".) A recall was issued; a search on the web will (with luck) reveal an 800 number. Winchester/New Haven Repeating Arms kept a record of which serial number rifles had the firing pin replaced. Another couple ways to check whether the repair was made is to dissamble the rifle and check the firing pin - if it's round, no repair has been made; if it's flat-sided, the repair has been made. A simpler way to check is to remove the magazine, retract the bolt, and look carefully at the top of the inside of the receiver; repaired guns should have a letter or number stamped into the metal. If there is no code designator, that is a good indication that the repair has not been done.