Scope ring reaming

[scottj]

So when is it called for to ream scope rings while installing a scope? I'm installing a scope on a 50 BMG Ultramag upper. Is this something that only most perfectionist riflemen do or what?

Scott

[ocabj]

It's actually called lapping.

The reason for lapping is to make sure the scope ring inner surface are straight with the tube due to imperfections in the rings and the mounts. This ensures that it maximizes the amount of ring surface that comes into contact with the scope tube which ensures a good grip of the scope. Also, it makes sure that the scope won't be bent by rings that are not perfectly square.

When you lap rings, you don't want to take too much off. You should only lap so that about 50% of the finish is gone.

When you lap rings, you shouldn't take the rings off and move them to another rifle or switch to another base. Once you lap, you typically need to keep the same base on that specific rifle that the rings were lapped on.

[Josh]

reaming the scope rings produces the same effect as lapping, just MUCH faster.

It will give you a perfectly uniform surface with 100% surface contact for the perfect fit to your scope. It also helps insure that the rings are not so far out of alignment that they bend the scope when your install it.

Just make sure you dont take off too much or your rings wont work, there needs to be that small gap between the bases and the caps so it can clamp down and provide some pressure on the scope body.

[rayra]

dab of rubber cement before clamping the rings will take care of the gription issue. Any excess can be rubbed off.
Don't see what difference a few thousandths on the rings would do, when you have to adjust the scope anyway.

[Nahuatl]

Ring Alignment

Whoa! Wait a second... a few thousandths of ring misalignment can actually bend your scope. Straight and true rings and scope are the single best thing the average rifleman can do to ensure the accuracy of his weapon.

There are two parts to a ring lapping kit.... FIRST you use the Alignment tools to get the rings as straight as possible. This is especially important with dovetail rings you can actually adjust, but even Picatinny tacticals or dovetails like on this Tikka can be persuaded a bit with hammer taps.



Once your rings are as straight and as you can get them - then they are lapped. A little dab of 220 or 320 inside each upper and lower ring, barely tightened, and 50 or so strokes with the bar. Clean, repeat as needed.



There are still plenty of things to do to mount the scope, but at least now you can see what it takes to get the rings mostly right. I haven't tried rubber cement. I usually use loctite red or purple.

[Nahuatl]

Ring Alignment

The Tikka shoots well, but it was ugly. Matte receiver, shiny blue barrel, black stock. This camo job took less time than my last girlfriend putting on her morning makeup.



Now it's got looks, what about results? As you can see, ring alignment pays off. These are break-in numbers.

Speed Check - All factory ammo
PMC 85 gr Sierra Game King HPBT 3001, 2935, 2914 @ 0.78"
Federal 70 gr Nosler BT 3380, 3399, 3381 @ 0.63"
Remington 75 gr Accutip BT 3246, 3301, 3285 @ 1.34"
Hornady 75 gr HP 3189, 3166, 3139 @ 0.62"
Remington 80 gr PSP 3250, 3270, 3256 @ 1.87" ((lead softpoint?!))
Remington 80 gr HP 3356, 3358, 3324 @ 0.97"

[scott.cr]

I agree with Nahuatl. Since every rifle is a little different in tolerances, every rail, ring and so on are all a little different in tolerances... things can "add up" and you can end up with a significant misalignment by the time all is said and done.

The conventional scope lapping kits work well enough. The first time I did this, I used a 0.999" chucking reamer, which was actually a 1.000" reamer that was .001" undersize. I milled a little off of the mating flats of the rings and reamed with the chucking reamer. It was a really nice-looking job, but beyond the realm of most rifle tinkerers.

[rayra]

To what end? Why is it worth the trouble? How does this process improve a rifle's accuracy (much less the shooter's)?

If you are properly sighting-in / adjusting your weapon, how does the scope's 'perfect' tube alignment bear in any way on bullet placement? For that matter, how does this extra procedure contribute to reducing group size at all?

And nahuatl, are you saying you put loctite between the body of your scope(s) and the bearing surfaces of your rings? Or did you mistake my mention of placing rubber cement there to be referring to the mount screws (where one would normally place loctite)


Sory, just not 'getting it' and looking for an explanation of why something that seems over-the-top compulsive to me would be necessary to hit a target.

Or is this just a difference in mindset between hunter-military and paper-punching?

[xenophobe]

Now it's got looks, what about results? As you can see, ring alignment pays off.

How does that prove ring alignment pay off? I didn't see any before and after groups....


Lapping your rings has very little, if any visible benefit. When it comes to high powered rifles shooting long distances, yes it will make a difference in consistency. On a standard hunting rifle or varmit gun, it will make little to no difference AT ALL.

Any one single factor in accuracy will be more important than having lapped rings. Work on your breathing, or your trigger control. Mirage is more of a problem than unlapped rings, IMO.

[ocabj]

Lapping rings isn't meant to increase accuracy. It's meant to preserve the integrity of the scope.

I think lapping rings is a small price to pay to ensure you don't damage your scope.

[onley11]

I've been rubber cementing my rings for a little while now too, and it makes a surprising difference in scope shift and any marks on the scope.

I end up with an even film on all surfaces and it works great.

It may or may not have an effect on accuracy, but it does keep my scope from shifting in the rings at all, and theoretically it could do other good stuff, but of course I can't prove it and don't care. Did I mention that it's basically free and you can't screw anything up?

What I do is goober up the upper and lower rings with the rubber cement and don't mount the scope yet, you need to make sure the rubber is dry and as covers the ring completly. Once dry if you rub the rings at all, you will lose your coat of rubber. Even if you really goober it on, it will dry into a thin film. When the rings are dry I put just a little more cement on the rings and set in the scope, ensuring the crosshairs are properly alignend. I let the scope set in the rings for 20-30 minutes before I put a little more cement on the top halves of the rings and mount them. As long as you're careful, you won't lose your crosshair alignment.

I usually won't shoot the gun for a day, and when I do remove the scope from the rings after this deal, the scope is unmarked, and it feels like its bedded into the rings, really tight, this setup WILL NOT move in it's rings.

BTW all the excess cement will rub off really easily.

Try it, what could it hurt.

[scott.cr]

If the rings are not aligned you will be bolting a straight scope tube into a solid holder that is not parallel and concentric... and when you tighten the bolts down, something will give.

[onley11]

The system will be under tension, more than it would already, but if it is off enough to make a practical difference, there is something very wrong, and you would have to lap it out of spec to fix it.

If you want to spend the money, and think it is an issue, do it. If I were mounting a 2000 dollar scope, I'd do it just to make sure everything was in spec to begin with. I've bought too many "cheap" scopes that just won't die to belive the hype. And yes, I am a master class nra highpower sporting (scoped) rifle shooter.

If it floats your boat, do it. But I won the last match with a 4X30 bsa fixed power unlapped scope. I use that 26 dollar beauty on my cali legal ar match rifle for a tactical scope. Just like the nc star 8-24x50 I've been using for 6 years, I'll shoot it till it breaks. They are both still going strong and winning matches.

[ocabj]

And yes, I am a master class nra highpower sporting (scoped) rifle shooter.

There is an NRA sanctioned "high power" category that allows scoped rifles?

[onley11]

Yup,

NRA Highpower Sporting Rifle.

Check the link-

http://www.lemongrovegunclub.com/index.cfm?ct=32

It's fun, try it sometime.