Help! M77 ring halves mixed up ...


Well-Known Member
Jan 23, 2010
Hi All,

Busy with my Ruger M77 scope mount and not knowing this, had my scope rings sent off for camo coating ... now to my horror and disgust, the clever people on the net tell me that you should never mix up your ring halves as the are grinded to fit their bottom halves!

How can I determine which is front/rear and further which way around? ... or is my only hope trial and error for accuracy?

Please advise also of a flat screwdriver to fit that big slot to tighten the rings to the integral base ... thanks!
Since the Ruger rings aren't factory matched, you might consider lapping them when you remount the scope. The process is pretty easy and there are kits on the market to do the process. Basically you mount the lower ring halves in alignment, then use a lapping bar and fine grit to make sure you get full contact of the rings to the scope, with no high or low spots that might induce stress in the scope tube.

I'm not sure what the bearing surfaces on a camo-dipped scope ring look like. Do they mask them to prevent the camo material from getting on those surfaces? If not, I'd say that lapping would be a must.
Thanks gent's, the surface touching the scope is not coated thankfully... I did ask them not too. The scope is coated... Not sure if that would cause grip problems? I have never lapped rings and might do so if i have accuracy problems. What if you had to remove scope after lapping? Surely it needs to be done everytime you re-fit the scope? Do you trust the screw type rings for the ruger m77?
Generally after you lap the rings you could remove them and replace them to the scope without relapping. If I have to take a scope off a rifle, I just leave the rings on the scope and remove the scope and rings together as a unit. As long as you push the scope forward a bit as you remount the rings to the bases, you probably will retain the same zero.

If you take the scope and rings off separately, you also shouldn't need to re-lap. Just don't mix the rings up! Mark which is front and back, and make sure you mount them with the same sides facing forward that you had to start with. Once they've been lapped, they've basically become like those high-end rings mentioned above. You'll also want to keep the same upper rings with the same lowers, and facing the right direction. A bit of masking tape to hold everything together in the correct orientation will make it all pretty easy.

I doubt you'll have issues with the rings gripping the scope. Not sure how thick your camo coating is, though. I was of the belief that a lot of the rifles that are camo-dipped actually dip the scope and rings together, after they've been mounted.
Youtube and the net are full of tutorial videos. Here is one on the ruger system

I use redfield jr. type bases and lap. If your using a piccitinny bases and high end rings or better imho the Burris signature rings with the inserts you will have the same benefits of true alignment and no ring marks. If your getting ring marks on your scope you need to either upgrade or lap or both. With the proprietary ring/mount of the Ruger I would lap the rings you have and be done with it. Use some birchwood casey cold blue or blue marker after your done for some protection for the naked steel if that is the material of your rings.
Good luck
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Take the rings and see if there is any matching angles or machine marks that will identify the correct position of each ring half. Snug the screws down and then check with a inside micrometer or dial caliper. to check roundness. It won't be perfect round as they insert shims between the halves when machining to allow space to solid clamp the scope tube. Angle measurement should match in and X at a 45o angle to the half slot. Feel to see if there is any inside off set in the matching of the halves. I got a set of the pointed sets of alignment points in a Torque Wrench set like shown in the U-tube. The rings must align on the same vertical and horizontal plane. Since a scope does not have a 360 swivel in middle of the tube. Use the full straight solid bar to align the rings. A M77 because of the offset in the receiver bridge make sure the tall base ring is on the back bridge of the action.

When I work with a new set of scope rings. I remove all cap screws except one and swing the cap off to the side and very careful on the match flats make 1 small mark on both halves that is visible. Take the 2nd ring and remove screws except one and swing cap to side and mark this ring with 2 small marks on the flats. Now just match the marks on the flats. Caps are now matched to ring and ends are matched.
thanks once again guys, please check my pics later on the rifle (new thread)... mounted the scope without lapping etc....hoping to get some groups and if that fails will return to the advice you have given ...:)
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