The single most-common reason for an SKS to have a non-intentional discharge is that the firing pin channel is gummed up with cosmoline (a greasy/waxy military-grade preservative. So many of these rifles were made, then stored in military armories, that the majority of the rifles that come into private possession arrive coated inside and out with cosmoline. The new owners typically clean the rifles fairly thoroughly, but frequently neglect to strip the bolt and remove the cosmoline from the firing pin channel. Subsequent incomplete cleanings leave dried-up chunks of cosmoline that can break loose and jam the firing pin in the forward position. Thus, either slamming the bolt home with the firing pin frozen in the forward position, or simply vibrating the spring-loaded bolt (with the firing pin frozen forward) against the primer can cause the cartridge to be ignited.

SKS – sniper gangster Simonov (СКС – снайперный карабин Симонова).

Think about this one…

The dirty Russian gangsters and their(THIS IS VERY IMPORTANT!!!) *DIRTY* rifle, are cruising around with the rifle’s bolt ‘locked’ into the *REARWARD POSITION* and with several cartridges in the magazine. The rifle is sitting with the butt on the floor with the barrel pointed upwards. The pumping soundsystem knocks the bolt out of the rearward position and into battery. BUT WAIT! Because the dirty Russians never cleaned their dirty rifle the floating pin of the SKS is all gummed up with residue, and is stuck in the forward position. When the bolt comes forward… SLAM FIRE!

This is something that is VERY common in SKS rifles that have not been cleaned in a long time. It is well known in the firearms community that when you release the bolt to chamber a cartridge and a round ignites (slam fire) you need to clean your SKS because the pin is getting stuck in the forward position. This happens because there is no spring to pull the pin back into the housing.

It is a dangerous weapon.

Run the feeder at the same frequency as the rifles
fire rate.Obvious?

How far would you have to drop the rifle onto a hard surface for it to self fire?

The firing rate ( frequency) of the rifle would
be well within the range of Audio frequencies.

This would mean that the firing pin is oscillating
in its housing at that frequency.

Try attaching the rifle to a parts/materials feeder, these things can shift several hundred
tons per hour rock if you want a big one, and
try again!

Your problem was that you were expecting the air
to transmit the force.
The rifle was probably sitting on the car chassis
effectively hard coupled to the speaker.

What happened to me: I had a hot bowl of soup, to hot to eat. So I dropped an Ice cube into it. The ice cube “exploded”, into about 5 peices, and I had soup spread about 3 meters away from the bowl!

So I think it’s about causing stress fractures in the ice to explode.

This doesn’t have anything to do with the spring on the firing pin (or lack thereof.) The spring is there to help retract the firing pin after a shot is fired. If the firing pin channel gets gummed up, the firing pin can get stuck in the forward position. When the bolt closes on a new round, the protruding firing pin hits the primer and the gun immediately fires. This is usually the cause of “full-auto” malfunctions and slam-fires, but it won’t cause the hammer to inadvertently fall.

Tom