Home Forums Hunting & Shooting Gunsmithing Looking for a specific hole spacing for scope base...

I own an original Stevens 44 1/2 chambered in .22 LR that my great-grandfather bought new with a 6x J.C. Stevens external adjustment scope as a package. Long story short, I'd like to use a modern scope on the rifle. It is D&T'd for the Unertl-type blocks that are original to the package. Center to center spacing on the rear block screw holes is .805". Where can a guy get a scope base that will fit on this? I know that CPA Rifles sells a modified Weaver 63B base for use with their barrels because I have one for the .30/40 Krag barrel they made me - and the hole spacing is not correct for my original barrel. I'm in conversation with Gail at CPA about it, but thought I would crowd source a little bit here also. Suggestions?

Wow. I didn't think I'd run into this much difficulty.

I used to have a spec sheet for Weaver bases, it was from at least 20 years ago. I am sure there are twice as many Weaver styles and sizes today. You most likely need an older base that may or may not be in current production.

Find an older, small gun shop and ask to dig through his supply of weaver bases or do the same with a gunsmith who has been around for a good while. You will probably find exactly what you need, but may have to settle for a base with a third hole added.

It would seem the easiest thing to do is contact Weaver, but I am not going to say that. They have changed hands a few times. Perhaps they still have their spec sheet available and possibly on their website?

I don't care about a third hole in the base. I just need two of them spaced correctly. Thanks for the help!

You have an orphan pattern on the hole spacing. I have the Weaver chart and none of the Weaver bases use that hole spacing, which suggests that other manufacturers probably don't either. The closest I could come on the Weaver chart is .812" spacing.

You may need to get some gunsmith bases and have them machined to fit your action or find a ring that will fit the existing Unertyl base. Another option is to find a Weaver style rail and have it drilled to match your bolt spacing.

Good luck with your search.

Bob

Get with Steve Earle,...he'll get you lined out.

Bob, are you referring to something like what Brownells has here? http://www.brownells.com/optics-mou...lank-scope-ring-base-stock-prod9851.aspx If I got the 9" picatinny (only because the Weaver is out of stock) I'd be set, correct? Then I have to find someone to radius the base, mill a relief in the bottom to accommodate the action, cut cross slots, and drill holes with the proper spacing. Anyone on the 'fire do that?

I'm not sure what you're trying to tell me here.

steven.m.earlecomcast.net

scope mounts, rails for your European target rifle, miscellaneous doodads and parts, etc.

That would be one way to accomplish the task. I believe Leupold still sells Gunsmith bases- basically their two piece bases as a solid rectangular block in the blue. Just shape the bottom to fit the action and drill the screw holes to match your spacing.
Or, you could get the closest Weaver type bases at .812" spacing and have someone with a mill use a small end mill and slot the existing screw hole and counter sink .007" and put them on. A little black Sharpie pen on the aluminum and you'll never see the cut and it would be under the ring anyway.

Lots of ways to skin this cat. I could probably do it on my little 3- 1 Smithy mill.

Bob

Thanks for the clarification on Steve Earle - I was trying to determine if it was a joke about the musician that went over my head. I'll post some photos in a minute that will add some depth to the issue at hand. What Bob is talking about "should" work because I already have a base partially modified for this rifle.

Okay, some photos. First, the rifle with matching scope mounted.



Next, a top view of bases w/o scope.



Here's the problem.



Profile shot of the milling already done on the base by CPA to accommodate the action.



In this photo, one can clearly see that there is plenty of material to offset the rear screw hole as Bob suggests. But I don't have the equipment to do so. It would also leave the other screw holes untouched as I would like them because the other barrel for this rifle is a .303 British and it would probably be best to have the scope mounted on unslotted holes for recoil reasons.



So - what's the best solution? I like the idea of slotting the rear screw hole. But I don't have the equipment. I might have a guy here in town that could do it, but he's not a gunsmith. What would it take to do the job?

Am I assuming correctly that the modified 63B base used on the .303 Brit barrel is only attached with two closely spaced screws? If so, that seems not to be very robust.

If the two screw attachment arrangement works for the .303 British, why not just start with a new, unmodified 63B base and simply drill and counter sink one virgin hole .805" behind the the most distal factory hole to fit the hole spacing of the .22lR barrel? I suspect that an epoxy under the base would help secure it to the barrel and if need be, removed with a heat gun.

http://www.brownells.com/GunTech/W-R-Weaver-Company-Mount-Base-Specifications/detail.htm?lid=11214

http://www.brownells.com/GunTech/W-R-Weaver-Company-Mount-Base-Specifications/detail.htm?lid=11215

http://www.brownells.com/GunTech/Weaver-Top-Mount-Bases/detail.htm?lid=11875

I have had to make weaver bases from scratch, but usually I get some weaver base length and 1) change the radius on the bottom with an end mill or a boring head [aka Steve Acker]. 2) Drilling the clearance holes in the Weaver rail is easy, exact depth countersink is a little harder.

Best to do this in a mill so you can get accurate spacing on the holes and the contersink is correctly drilled for depth. It looks like you could move the base back enough to drill 2 brand new holes to fit the spacing and have a more solid mounting base. May have to invest in a countersink to complete the job.
If I had the proper countersink I would do it for you on my mill.

Bob

No. On the .303 Brit there are four base screws used. CPA d&ts spacing both for the 63B and blocks per my request when they built the barrel. For .22LR the two base screws should be plenty.

Thanks, Bob. I checked with my local guys and it's smaller than they can work on. I'm still waiting to hear back from Steve Earle.