Your shotgun was manufactured by Hi Standard as their Supermatic model C1200, no later than the early 1980's. Suitable scope base mounts will be difficult to find.
I have a savage 6400 30-30 with a side mount scope base. The scope was added for my 13th birthday 20 some years ago but Im sure you can still get it done.
Marvel Custom Guns makes a scope base that replaces the sight rib on a Victor and uses Weaver rings.
The Ballistic Enterprises #1 INTEGRABASE, is absolutely the best scope mounting base ever manufactured for the Benjamin and Sheridan air rifles and pistols. It is constructed from aircraft grade aluminum and is CNC Machined on the latest equipment. This scope mounting base mounts the scope with proper eye relief and closer to the bore axis for more comfort and better scope tracking. Available through several major airgun distributors throughout the United States.
Weaver N series, N2 being the lowest height and N5 being the highest for bolt clearance. N2 is most common and should be fine for most variations of the 101.16s.
That gun was made by Marlin for Sears, and those holes are not factory. Someone has drilled and tapped it for (probably) a Weaver side-mount base.
Just today I put weaver rings on mine. They have a 3/8 dovetail base and 1" scope rings. I had short 1" rings but I could not remove my bolt for cleaning. The rings I replaced the rings with the above mentioned. 3/8 dovetail mount 1" rings fro scope mounting see thru mounts for use of iron sights And the most important part of all is the 7/8 rise of the new mounts.
Hello: Weaver offers a scope base for the Marlin Model 512 Slugmaster, contact Weaver for a complete package. Thanks side scope mount (Weaver 10M)
You can order one from Numrich. I have this same gun and it's a Marlin Model 80.
The JC Higgins Model 45 is simply the Marlin Model 336C as made for Sears. The base gun is still in production, although Sears is no longer in the gun business. www.countrygunsmith.net
Your J.C.Higgins is a sears name that was made by Savage.It is the model 6,or 87.I would use these madel numbers to cross reference the correct scope base and rings for your firearm.I would look at the old redfield mounnts as they made these for a lot of older model firearms.Good luck in your search.
the model 36 marlin was not drilled and tapped for scopes as it left the factory.I know because I have two of them.Your rifle may have been done by a previous owner as it was common to have a scope on a rifle during the last 50 yrs. You may by a model 336 base,be it 2 piece or one and see if the holes line up or have a qualified gunsmith inspect it and have him match up the mounting holes to a scope base.
The proper base/bases and rings.