Weevil

Bought a M77 Varmit 220 Swift in 75 ,....My first new rifle .....I was 15..... It came with target blocks ,Gunsmith said here are the rings you don't need those. Here I am 37 years later and I am wanting a set so I can mount a Unertl scope to target blocks . Anyone got any Idea what the thickness of the front and rear should be . My barrel is tapped for them.I believe they are 6-48 but not sure .Anyone have a set they would part with,or know how to get a set of factory or specs for them . Looking at Ruger diagrams they are not shown ....Thanks

Roundball

Back in the day I had a 2" Ultra Varmint mounted onto my 77V Swift. The spacing of the factory blocks appeared to be for a Lyman scope. It was necessary to drill, tap, and install another scope block to accommodate the Unertl scope. I would suggest making sure that scope would work on the factory spacing etc. The old guys that could do this work locally are all gone now. The 77V 220 Swift makes for one fine varmint rifle.

Weevil

The factory blocks should accept Lyman or Unertl but not Fecker as they are a little narrower , but Fecker mounts can be used with Unertl or early Lyman . Not POSA but think Lyman had a newer mount later a Posa that has a another cut or could be another micrometer style ring
....Anybody .....Any Clues.....?????