ARH, I have the Crosman equivalent (Sierra-Pro), but never seemed to have such a bad re-coil that the scope would shift as much as what you've described. When you say the stop pin is shearing off, I assume you mean the one that bolts down through the rear of the one piece mount. All I can thing of, is to make sure this stop pin is deep enough into the stop-pin hole located in the top of the action. Another thing you may try is to flip the locking plate of the mount and see if it grasps the dove tail grooves any better. Not sure, but I think it can be flipped for 3/8" and/or 11mm dove tails. Another suggestion would be to really torque down the bolts holding the mount in place. For cheapo mounts crosman provides with this set-up, they are pretty tough, and you shouldn't have too much risk stripping out the threads. If you do, you can always retap the holes a size bigger and get a stronger "bite" on the mount as a whole. When you place the mount on the gun, leave the pin extended a tad until you feel/hear it 'click' into the stop pin hole, then 'snug' the plate to the mount. Next set the stop pin until it becomes snug in the action,.....not too hard though!!!!, but enough that it 'seats' into the action.....then torque the mounting bolts evenly, alternating them,.....say, front bolt, third bolt, second bolt, rear bolt etc., and repeat this until it's locked down. This is the method I've always used, and have had good results with this proceedure. Later on after breaking in the gun, I would advise getting it tuned. That's the best way to smooth these rifles out. Good Luck, and hope this might solve your problem!!!! tjk
PS, If you're stop pin is totally sheared of, you'll either have to order a replacement, of if posible file down the pin some to get more of the 'nimple' back.
