Rifle Scope Tools  1            8-2015


Mounting a New Rifle Scope

I bought a new scope for my hunting rifle which has been long overdue. The one that's on my Remington model 700 chambered in .270 has been on that gun for over 30 years and has worked great all this time. But now that my eyesight isn't what it use to be, I decided to buy one with a little more magnification.

My old one that you see below is a Leupold Vari X II, 3 X 9 with a duplex reticle mounted with Redfield rings and base. Now this setup has worked flawlessly all this time, well almost the whole time. Last year I had some trouble adjusting the 'power ring' possibly due to the scopes old age along with the cold weather that I was hunting in. I fixed one problem by making a new power ring right after hunting season but I couldn't change the magnification.
 

 

 

This old scope sure has seen a lot of miles and a lot of beautiful country side but now it's time to retire it and go with something new. Oh... one other thing, my new scope won't need the power ring that I made because it's already built in. Oh well, I had fun making it.
 

 

 

With a snap of the hex key as I loosened each screw, here is what I found once the old scope was removed. The rings don't look as bad as I thought they would with only a small amount of rust here and there. I mean this rifle has been in all kinds of weather and even underwater once (my horse rolled while I was crossing a river in Utah) so I was pleasantly surprised.
 

 

 

Close-up of the top ring which doesn't look too bad. With the old scope out of the way it was time to do some work before I fasten the new scope down.
 

 

 

Now that the scope has been removed I can check to see if both rings are in alignment. To check the alignment I made some pieces out of 1.000" diameter X 4" long steel that will clamp into the rings. I also squared the ends to the outside diameter so they were nice and flat. Once rods are clamped in place, this will show me if the two rings are concentric or not and if there's any out of square condition too.
 

 

 

I placed the rods so they were equally spaced between the rings and then clamped them down. Notice the alignment is off slightly. This isn't good and looks like my old scope was off by this amount. This puts stress on the scope tube which is a bad thing and can lead to problems.

In case you're wondering about the shiny area on the rods, this is where I sanded off the burr that was created after facing (squaring) the ends.
 

 

 

Now this shot is from the side and the one above is looking down. That means the rings are off in two directions, to high and over to one side which is bad news. On the other hand the two rod ends are parallel to each other, which is a good thing. This can be fixed pretty easily which is what I'm going to do next.
 

 

 

The diameter of this piece of steel is also 1.000" which will be used to help put the two rings in alignment. This piece was 8" longer but I cutoff two pieces that were used above. I found this piece laying around at my work in the scrap pile but it came in handy for this project. I'll call it a 'lapping bar' as it will become the tool that will help put both scope rings into alignment.
 

 

 

I drilled and tapped for a 1/4-20 setscrew which keeps the handle in place.
 

 

 

I clamped the lapping bar so that it had light pressure, offset the handle, pulled the bolt out of my gun, placed a rag over the action and then smeared some lapping compound on the bar. By working the lapping bar back-and-forth along with turning it at the same time, I started lapping in the two rings.
 

 

 

Here you can see the crosshatch pattern that was left on the bar. This pattern will also be left on the inside of the rings which is what I'm after. It didn't take long until I needed to tighten the screws a little more and then work the bar back-and-forth again. I did this a few times and then checked my progress by pulling off the top half of the rings.
 

 

 

Here you can see the lapping compound being spread all of the bar. It was messy but it worked great.
 

 

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