Scope Ring Lapping - shoot first, or lap first?

[jrpascucci]

Hi,

So, I have a new neato scope for my AR. I also have a cheapo scope for my other upper, and a lapping kit from Wheeler.

Questions:
1) Should I lap the scope rings before I take it out to shoot? Or run a few rounds through it to get things settled, make sure my eye relief is adequate, and then lap? Or lap, then shoot, then lap again?

2) Is it worth lapping rings that are mounted to a quick-disconnect?

3) Is lapping more or less helpful with quality rings and optic, than with crappy rings and a crappy optic?

4) After lapping, should one apply a new surface finish to the rings, or bluing or something? Just oil?

 

[mac1911]

If your going to lap do it before. To much time wasted wasted the other way.
Since you have the kit you should at least try it. I would give it a go on the cheaper rings and scope you plan to use.
Just make sure you mark your rings position and cap position.
Your not just lapping the "roundness" of your rings but also the slight mis alignment front to rear of the assemblies themselves.
Now if you want you can mount and zero the the rifle. Then lap and see just how much your zero changes?

 

[DW357]

I'm thinking I may have to lap the Leupold scope rings on my 44 revolver. I had the screws cranked down pretty tight and the scope would slip forward probably 1/10" under recoil - I also shot 100+ rounds of 44 mag which was a lot. I may try some friction tape or grip tape first before I attempt any lapping....

 

[Wendell]

Brownells might sell you powdered rosin (to prevent the slip).

https://www.brownells.com/gunsmith-...essories/vise-accessories/rosin-prod1123.aspx

If you can't get it from them, Amazon has it.

 

[mac1911]

Brownells might sell you powdered rosin (to prevent the slip).

https://www.brownells.com/gunsmith-...essories/vise-accessories/rosin-prod1123.aspx

If you can't get it from them, Amazon has it.

Did you ever lap your rings?

 

[enbloc]

Anything Worth Doing... Is Worth Doing Right...

 

[Wendell]

Did you ever lap your rings?

Yes. Brownells will sell you virtually everything you'll need (with the possible exception of the rosin, but Amazon does have 'powdered rosin' listed).

 

[mac1911]

Did it help, how bad where the rings/alignment ect?

 

[jrpascucci]

Did it help, how bad where the rings/alignment ect?

I used the two tapered-to-a-point gauges, and they were a bit off to my eye in both the good and cheap rings.

I lapped until it was easy to lap, then tightened, about 4 times, stopping at only a couple of ft-points of torque. When I pulled it off, I saw that the finish was removed and got to a fairly consistent bare metal. When I cleaned and put the gauges back in, I had to turn the upper around against a white sheet of paper to make it clear in which direction it was off, and it was barely not perfect, which I thought was good enough.

I haven't used the drill attachment, I was doing it by hand.

I haven't yet torn the good one down yet to do it a second time after shooting, it has held zero over a couple of outings.

After lapping, I still wasn't happy with the cheapo scope and rings, and replaced them with vortex. So, I lapped the vortex sporter mount, which also was just a touch off by the gauges despite being one piece, and also removed some finish and got it to a bit more consistent sheets of bare metal (not, obviously, at the sides where it flares out to the screw block). I'm going out to zero it right now.

My current theory is that the most significant effect of lapping (given my experience with the sporter mount) is to pull down any high spots - some of which might be from variations in the finish - which will provide a more consistent friction across the whole surface of the scope-mount interface.

Right now, I'm not 100% sure how much variations in a pair of separable rings would be assuaged just by lapping, since the other interface would be at the pic rail, as that could have similar high-point issues and experience variance due to that. Maybe that's where post-shooting lapping and even the drill attachment would become more helpful.