I purchased on of these for my new RWS Model 54, Air King. This is a very powerful air rifle known for damaging scopes quickly. I mounted an inexpensive ($150) 40 MM scope on it and zeroed it at 20 yards. Once I found the right pellet I began putting one pellet inside the hole of the previous one, one after another, after another, after another, etc. (all day long). No issue with accuracy at 20 yards and beyond. I have taken shots out at 50 yards and beyond with incredible results, as long as I do my part. With regards to using the mount with a shorter scope, simply loosen the allen nuts that secure the rear ring to the rods, and slide the ring up on the rods a little. It increases the spring tension a little but it still works great. I had to do this to mine. The good thing is that this mount works; it mitigates the effects of forward recoil and allows the use of less expensive scopes on heavy recoil rifles like the Model 54. Love it! I have had it for many months now a still no issues. I have recommended this product to friends.