What is the proper scope base for a Ranger 22LR with heavy target barrel?

I seem to recall that may be the same gun as a Stevens 416.

Most of those guns did not have drilled and tapped recievers. They did have drilled and tapped barrels for old style target scopes. You will probably do better to take it to a competent gunsmith and have him drill and tap it to fit a currently available scope base.