First, welcome to the forum. When you get a minute, stop over in the intro section and say howdy.
Does your new Mossy have two parallel lines on top of the reciever? Slightly undercut, and 3/8ths of an inch apart?
THOSE are for mounting a scope. There are rings made for a .22 that grip the edges of those two "dovetail" cuts. No drilling and tapping, you use a GOOD screwdriver to mount them. Even WalMart carries them.