The tappings are all the same, where things get specific is in the design of the top of the receiver where the tappings are. Some are rounded, some hex shape some flat, the scope mount must conform to that design to be solid. Not familiar with the Rossi ML, best bet is to take the gun to a gun shop and see if they can fit the mount to the gun, not install, just fit. The install is a breeze, no need to shell out the clams for that. If you can provide more detail (measurements) on the receiver design perhaps more help can be given