Scope Bedding?

[Onyx Z]

My PST 2.5-10x32 appears to have shifted in my ADM Recon mount. When mounting originally, I cleaned the rings and scope tube and mounted dry, tightening the rings pretty dang tight (not cross-threaded) with the turret in the center of the two rings. When I pulled the rifle out last weekend, it looks as though the scope slid backwards in the mount. The scope cannot physically be moved by hand, but it looks as though recoil may have caused the scope to shift. It has never been abused or dropped, but I do swap the optic between rifles occasionally.

This optic is only used on 5.56 rifles.

I know you can bed an optic in a mount, which may be the best option. What are my options for bedding a scope in a one-piece mount?

[GH41]

When you installed the scope did you tighten the bottom ring screws first? Did you tighten the upper screws to the recommended 25 inch pounds or just guess at it. In bolt gun applications they may bed the base to the gun. They may also lap the rings. I have never heard of bedding a scope in the rings.

[Eurodriver]

Onyx, As a recent graduate of "Scope mounting 101" I can say that what Google tells you is true. Lap the rings, align the rings, and use a torque wrench.

With the ADM recon mount, you obviously don't have to align the rings. You may not have to lap them, either. However, I would as it is cheap insurance. Then always always use a torque wrench to tighten the rings to spec.

Lastly, maybe your scope didn't shift at all? I always put a witness mark in pencil behind one of the rings. Also, if your scope is moving your zero will be moving with it. Have you noticed any issues with it when firing?

[Onyx Z]

I did tighten the bottom screws first, then the top. I just checked the torque and it is at least 25 in/lbs.

It holds zero throughout a day of shooting just fine. I would definitely know if it moved during a day of shooting since it wouldn't hold zero. As for holding long-term zero, not sure since I swap it around to a few different rifles. But overall, I feel like it has held zero for the most part.

Looking further into it, it may just be my OCD kicking in. On one hand I feel like it did in fact move since it's not centered in the mount, but maybe I accidentally bumped it when aligning it and never noticed until now?

[Slippers]

I wouldn't lap the rings on a one piece mount without checking for concentricity first. It probably isn't necessary to lap.

Did you thoroughly degrease the rings before mounting? ADM ships them with quite a bit of oil applied.

If you're worried about slippage you can use a little rosin powder under the rings to really lock the scope tube in place.

[Onyx Z]

I wouldn't lap the rings on a one piece mount without checking for concentricity first. It probably isn't necessary to lap.

Did you thoroughly degrease the rings before mounting? ADM ships them with quite a bit of oil applied.

If you're worried about slippage you can use a little rosin powder under the rings to really lock the scope tube in place.

Yes, both the scope tube and rings were thoroughly degreased beforehand. I never thought about rosin powder. I may have to give that a try before lapping.