Spring-loading to shoot the bolt and the existence of lever checks/trips surely indicates the maker's intension of self-locking. Has to be a "want of a nail" scenario. You don't lube and don't clean and relube and the bearing surfaces of hinge and pin and lock engagement wear. Add powder residue and good old natural abrasive (mineral sand and dust about hardness 7 on Moh's Scale)and I'd bet there's no difference in wear when easing the bolt home or letting it go by itself. So now there's a bit of slop or takeup and you get Rocket's battery effect on firing (like a yard engine backing onto a string of freight cars and every coupling slamming against the next).
I "shot" a sizable bunch of teenagers and pre-teens at our club's Youth Day trap station yesterday with youth-stocked 20 gauge autoloaders. The psychological anticipation combined with bad form and ill fit does make for little "ouches" for some of the bantamwgts, but not so much for those (of whatever size) who can somehow focus on placing (or having placed) the butt correctly and tightly in the shoulder pocket. If you add a rugrat to the recoil train, you should make sure they're not off the face of the buttplate!
jack
