I want to make a one piece cantilevered scope mount base (for Talley rings) on a Ruger 1V to get the scope farther back.
I've tried the extended rings and they look terrible (at least to me).
I'm trying to figure out if the #1 has a horizontal surface (other than the bore line)that I can use to level it. I'll take the top of the mount down to parallel on the milling machine.

Thanks

Use the receiver sides and go 90 from that; that is your horizontal plane. Clamp on a 123 block and use your level. Or clamp on a 90 degree level. Anyway, go off the receiver sides.

1. Face of the receiver and I suspect your are not pulling the barrel.

2. The bore and chamber- you could make plug

3. If the breech block is square to the bore the breech block mortise could be used. If they are not square measure the angle and set up using that angle to get the bore square.

It does not have to be perfect. It may be of some advantage to have the plane of the mount running down hill from back to front to compensate for drop. That slope might be anywhere between 10 and 20 minutes.
That will help keep your cross hairs closer to the optical center of the scope when it is zeroed.


If you have been shooting the rifle with the original rib you may have some idea how well the original rib is aligned to the bore.

If you remember how many minutes the original rib is off you could line up on the original rib. If you don't remember just center the crosshairs to the scope tube or to the manufacturers instructions.

Mount the scope and shoot a group to figure out how many minutes the rib is off in the vertical.

Then remove the scope, rib and dowel pins.
Re-attach the rib using only the flat head screws and level front to back to suit your planned mount. Then remove the old rib and install the new mount base. Then mill your new top surface.

I agree with the outlook of SR4759. How the scope lines up with the bore sight is the most important matter, in the end.

I put a scope on to the dovetails of an Anschutz 1416 recently and, though things should have been level straight off, I found the scope pointing about six inches high at 45 yards. A couple of shims at the back mounts fixed the problem but it has occurred to me to mill down the front dovetail of the mounts so the scope looks a couple of inches low.

But do the shims work? Well, the first three shots at 50 yards were an inch low and right but grouped into a quarter inch.

OH, you mean parallel with the bore; I use a range rod in the bore and level off that. You can turn one out of brass or steel to fit into the bore and stick out enough for your level. But the breech block recess would be easier to go from.

Personally I would start out with a bigger piece of material, fit it to where you want it and using a scope and a pair of V-blocks, put a Collimator in the bore and take a look through the scope. Adjust the action up or down to compensate for elevation, something like SR 4759 said.

To set up to machine the quarter rib on my Number One, I first fitted the rib to the barrel contour. I then set the receiver in the vise and leveled the barrel by simply using a dial guage over four inches of barrel and adjusting until the dial read one half the amount of taper. In other words, with the barrel tappering from .756 to .692, I wanted the dial to indicate .034". I had contoured the barrel between centers and the bore looked straight so I figured it would be close enough. The barrel was supported by a jackstand and clamped in place. I then drilled and tapped the barrel for the rib (six 8-40 holes)then installed the rib while leaving the receiver and barrel mounted in the vise. I then took a cut along the top of the rib to make sure it was parallel with the bore then milled in the dovetails for the Talley rings I planned to use.
It must have worked out OK since I centered the adjustments on the scope and hit within 3 moa at 100 yards. I'm satisfied. Regards, Bill.

I always use extension rings on my NO 1s to get the scope back far enough.

quote:

Originally posted by Bill Leeper:
To set up to machine the quarter rib on my Number One, I first fitted the rib to the barrel contour. I then set the receiver in the vise and leveled the barrel by simply using a dial guage over four inches of barrel and adjusting until the dial read one half the amount of taper. In other words, with the barrel tappering from .756 to .692, I wanted the dial to indicate .034". I had contoured the barrel between centers and the bore looked straight so I figured it would be close enough. The barrel was supported by a jackstand and clamped in place. I then drilled and tapped the barrel for the rib (six 8-40 holes)then installed the rib while leaving the receiver and barrel mounted in the vise. I then took a cut along the top of the rib to make sure it was parallel with the bore then milled in the dovetails for the Talley rings I planned to use.
It must have worked out OK since I centered the adjustments on the scope and hit within 3 moa at 100 yards. I'm satisfied. Regards, Bill.

"Great minds..."

That is how I would have described it were it me.

I go about it similar but I turn a false barrel with that is cylindrical and keep the math simple. Either way it works out to be close enough.