Mounted on 22lr Winchester model 57. Rear ring is very fine thread. Purchase extra rear rings because its just a matter of time before it strips the ultra fine adjustment tread. Both on the ring itself and the set and adjustment screw. Especially if using differing grains of ammo. These will strip with just finger tightening. Be carful. The company WILL NOT replace for free. You will need to purchase new rings. About $27 with shipping
Cons: rings are crap
This review was written in the old system and had content requirements that are different than reviews written today.