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Leupold Adjusta-Mount Expert Needed

v35v35 Member Posts: 12,710 ✭✭✭
edited May 2014 in Ask the Experts
Is the front capstan supposed to be adjusted if you're out of down adjustment on the rear capstan? The front came solidly anchored down.
The rear capstan is about 1/16" above bottoming in the mount when its' screw bottoms out on the receiver but needs to be .034 lower.
I'm not keen on altering this rare mount or grinding the capstan screw.
The printed instructions don't mention it.
The mount is correct for a post war Mod 70.
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Comments

  • spiritsspirits Member Posts: 363 ✭✭✭
    edited November -1
    I have used one on a Mannlicher Schoenauer 1950 because it came with the rifle when I bought it. Also picked up ones for a Rem 721 and Win 70 (two piece) off of ebay just as collectables not to use. The capstans, good nautical term, should have all the elevation you require without bottoming out the hex slotted screws on the receiver. For the MS 1950, I used an optical scope collimator to adjust the scope initially at the house which was definitely easier than doing it at the range. The only things I noticed was that 1) make certain the scope ring windage screws set in the recesses of the split metal bands before tightening them up or you end up with more recesses than you started with, 2) everything will seem somewhat loose until you have everything together, 3) set the scope's elevation and windage to their approximate mid point, and 4) hopefully you are using a modern scope with internal adjustments to fine tune with at the range for zeroing the rifle.
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  • AmbroseAmbrose Member Posts: 3,163 ✭✭✭✭
    edited November -1
    Let me do some checking. I have several of these mounts. I am almost sure you can raise the front ring (which accomplishes the same thing as lowering the rear) but I'll check and get back.

    EDIT: Well, I'm wrong! I have two of these bases not mounted on a rifle and checked them both. That front stud (capstan), while obviously threaded in place refuses to turn, as you said. I don't see a lock screw so something else holds it in place--locktite? You could put a shim under the base at the front. I guess if I were dealing with your problem, I'd try gently heating the front capstan to break it loose. From your description, I'm guessing you are trying to mount a fixed reticule scope on an older Winchester to get a period rig. I have an Adjusto Mount on a Mannlicher Schoenauer, a Remington 721, an older Winchester 70, and a couple others.
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  • Ray BRay B Member Posts: 11,822
    edited November -1
    Both the front and rear mounts are threaded and turned using a 3/16 hex wrench. they are both clockwise threads. In order to maintain point of aim the front "bolt" needs to be tight against the base because unlike the rear mount, there is no click stops on it and since it is separate from the ring into which the scope ring attaches, if it isn't tight it can turn, resulting in a vertical shift in point of aim. If you need to raise the front ring it is possible to turn the bolt out then add a thin washer to the existing one and reassemble. there are only about a third as many threads on the front bolt as the rear, so there isn't much latitude for adjustment. This may not be clear so I'll see if I can post some photos of the parts.
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  • Ray BRay B Member Posts: 11,822
    edited November -1
    DSC_0218_zpse9be5903.jpg

    DSC_0219_zps313a5af7.jpg

    DSC_0220_zps029605c6.jpg
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  • AmbroseAmbrose Member Posts: 3,163 ✭✭✭✭
    edited November -1
    Ray: How'd you get that front one out? The two that I tried (a 2-pc. for a Sako and a one-pc. for a 1903-A3) would not budge and V35, the OP, has a similar experience. Also, in looking over my stuff, all 3 of my 721's have adjusto-mounts on them, one is a real early base that looks like it's made of some sort of blackened copper alloy. So it appears there were changes in these mounts during the time they were manufactured.

    BTW: Thanks for the pictures; they help a lot. I wish I was smart enough to post pics!
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  • Ray BRay B Member Posts: 11,822
    edited November -1
    quote:Originally posted by Ambrose
    Ray: How'd you get that front one out?

    I have a wood vise to hold the base without marring it and then insert the hex wrench into the center of the "bolt" and apply a goodly amount of pressure- don't know what it would be in torque pound/feet but it was just using the wrench and hand strength. it was quite tight. If there was any rust or adhesive to the threads I can see where it would be near impossible to get out, short of soaking it in penetrant.
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  • v35v35 Member Posts: 12,710 ✭✭✭
    edited November -1
    With the mount in a vise between wood blocks, a few good taps on the Allen wrench will loosen the front elevation screw (capstan).
    Unfortunately, only 2 1/2 turns and it's out of engagement so one can't do much shimming under the capstan.
    Shimming the front mount 1/32 will look crummy but will save the screw.
    I suspect someone put the wrong rear capstan or mt block in the kit. Capstan thread length is .335 on my Win 70 mount and .305 on a spare Mannlicher mount while .260 is what I need to avoid cutting metal.
    Anyone have a spare one .250 (1/4) thread length?
    I have 3 ea Balvar 8 and 8A scopes that with Adjusta Mounts, make for neater looking outfits (to me) than with Kuharsky or B&L mounts.
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