I used this rail on my air rifle , in place of the factory rail. The factory rail did not come back far enough for for my scope set up, due to my long LOP & the rifle was actually a little front heavy. The wide flat bottom of EGW rail made it very easy to mount, utilizing existing holes in the receiver flat top. The rifle has better balance now & I have a lot of rail space for various scopes. The shipping of this rail was super fast.