Three times in the last month, my son has pulled the trigger on a 1930s vintage Model 12, there is audible click without detonation, and then 10-20 seconds later the gun goes off (fortunately pointed donwnrange every time). All three instances involved different "name brands" of factory ammo. The gun has not had any FTFs.
I always thought hang fire resulted from an abnormally slow primer burn caused by a bad primer, rather than a too light a hammer strike. Can a light hammer strike cause the primer to slow burn leading to a delayed detonation?
In any event, the gun is going to the gunsmith, but I would be curious to hear any thoughts on what might be happening.
Thanks in advance, Doverham
