Yea - 18 inch/ pounds ??? I wouldn't think the scope tube would be that thin. I have a hand full of Vortex scopes myself, my latest one is the Venom, for the money I can't complain- yet. Do you have a stock action or box or a extended one. With a stock box you may be limited for O.A.L. what other slow powders do you have.Well I figured out 90% of the problem just now. Scope has slid over 1/4 inch. Thanks to vortex low tourq spec. That's my fault for not catching it sooner though