A brand new single shot Turkish 12 gauge, cannot remember the make, opened on nearly every shot. It was one of those folding actions with one coil spring activating both the underbolt and the trigger. Had my local spring man make a stiffer spring to the same external dimensions of the factory one. Problem cured.
I reckon that when the gun stopped against the shoulder on recoil, the inertia of the long underbolt lever, the one that hangs under the gun, was enough to compress the coil spring and retract the underbolt.
There are some older YT slow motion videos showing the effects of inertia on external shotgun parts, ie the oscillations of the opening lever on a Citori, the oscillations of the hammers on a muzzle loading SXS. It seems logical that if inertia can cause the top lever to oscillate left to right, it can cause the locking bolt to move back too. And if the movement is long enough the barrels are unlocked.
It would seem that the inertia driven moves happen after the shot has left the muzzle, so it is not such a major safety issue, but still, it is worrying. It should not happen.
I am not saying that the inertia of internal parts is the only cause, but it is a big factor.
Last edited by Shotgunlover; 11/29/21 12:42 PM.
