Looks like for Weaver TO-1 base - uses 3/8" 22 rimfire width rings.
Just looked it up, your right, the 3/8's dovetail is fairly silly though, I'll have to buy some real quality rings I suppose
They work OK. A lot of bases are held with that or fewer tapped holes.
Make sure you get the right screw and threads.
If you want to go "old school", I have several sets of the BA 20/21 bases and Parker Hale Rings that was the 1950's/60's standard way of scope mounting on a Lee Enfield. Parker Hale ( I believe it was them) made Envoy and Enforcers for Britain target and sniper rifles and used these bases and rings. PM me if you are interested - I am not exactly certain if the two holes over the receiver have the same spacing between the Weaver TO-1 and the Parker Hale BA 20 front base.
I was more thinking of the scope and rings moving backwards on the rail after shooting
I've had a Weaver TO-1 mount on a No5 JC since about 1962. It has always been a satisfactory set up. I changed scopes and rings on it a few times, but have used a Redfield 23/4X in Redfield 3/8 " steel rings for some time now. It is a great bush rifle and has gotten me a moose, a nice black bear, and a number of mulies and whitetails over the years.
On the Parker-Hale rings, they are meant to be tightened without a lot of torque. The screws are made of fairly soft steel and will break under excessive torque. Don't ask me how I learned this.
In my experience the Weaver TO-1 is a poor set up on the Lee Enfield. The rings do want to move forward under recoil especially with a more bulky scope. The Parker Hale set up is far superior in my opinion.
In my experience the Weaver TO-1 is a poor set up on the Lee Enfield. The rings do want to move forward under recoil especially with a more bulky scope. The Parker Hale set up is far superior in my opinion.
I wish Weaver would come out with an updated T01 with cross grooves/Picatinny base setup. Much more secure scope and ring holding.
There are those clamp on airgun mounts that put a Picatinny rail on a long groove like on a .22 or the T01 base.
Someone had also drilled a hole down through a ring right into the T01 base and drilled and tapped it so the ring couldn't possibly move- it was locked right to the base.
The problem with the PH stuff is they are long gone and you are scrabbling to find the parts and rings in museums anymore. I think the Weaver base is still made and it's fairly cheap.
A quick search yielded the T01 available in Canada for $18.99.
ATI had a base that used those holes. This one, I think.