I have 3 Marlin cowboys a 32-20, 38-55, and 45-70. A fit of nostalga caused me to mount the Leatherwood 3x short scopes on the 32-20 & 38-55. As can be expected field of view and light gathering capability are not up to modern scopes. But the optics are generally very good. Was also considering one for the 45-70 but changed my mind when problems popped up with the 38-55. The scope kept sliding in the mounts no matter how tight I tightened the screw in the ring that is supposed to hold the scope. Finally broke the screw, drilled out the original and installed a socket head screw tightened hell out of it, no help. Tried all the tricks normally used to prevent scope movement finally ended up with some green locktite between the scope and ring, holding so far. This occured with loads shooting 250 cast bullets at 1650 fps and the mounts sold especially for the Marlin. Makes me have serious doubts that you could do any thing to make it hold up mounted on a 45-70 even with the mild factory loads. Like the scopes a lot just wish the mounts were better. No problems with the mild recoiling 32-20.