Accurate alignment of scope rings

[BMG]

I have been viewing this excellent website for quite a while now and think it is a most valuable resource.

I was wondering what method you guys adopt to guarantee that the perpendicular center line of your scope rings are exactly in line with the perpendicular center line of the barrel bore. Also making sure that both rings are in line with one another so there is no lateral tension on the scope body when fitted.

I would like to fit Mk4 Leupold Tactical rings onto a Picatinny rail. Thank you in advance for your comments.

 

[dreever]

Brion,

You are sort of at the mercy of the base holes drilled and tapped on the receiver at the factory.
Having said that here is what I do.

I first mount the base to the action and torque the mounting screws to 15 inch pounds. Then I eyeball it, sometimes using a magnifier to see if the rail is mounted straight and if there might be a cant to one side or the other. There isn't much you can do if the rail isn't straight with the barrel other than send it back to the factory. If it's canted, you can always bed the rail to the receiver to get things straight again.
An inexpensive tool is a wooden or metal rod 1' or 30MM depending on your scope tube that's long enough to set in your rings and extend down the length of the barrel. You'll soon see if things are straight that way. The longer the rod the more obvious any crooked base will be.

OK, let's assume your base is good to go, WHEW! you breathe a sigh of relief and now proceed to the rings.
Install your rings where you want them on the rail and push them forward while torquing each of them to the recommended inch pounds,65 for steel, 55 for aluminum) you push forward because this is the direction the scope will move during recoil.
Now take the appropriate size lapping bar and insert it into your rings. Now put the caps on and torque them to 15 inch pounds. You do this so the caps will take a set to the bar, not your expensive scope tube,this is per Nightforces recommendations). Now remove the caps always making sure they stay oriented to the ring halves they came from and proceed to lap your rings. There are schools of thought as to lap or not to lap, but in my opinion it's cheaper to lap a pair of $100 plus rings than to screw up or mar a $1800 scope tube. Again Nightforce will not warranty a scope damaged by not lapping rings. It's cheap insurance.
Now you can mount your scope paying attention to eye relief, and reticle cant. The easy way to assure dead on reticle mounting is to go to an auto parts store and buy a good set of feeler gages that are removable. With your scope tube setting in the rings put enough gages together so that it just fits between the top of the rail and the flat in the center of the bottom of the scope tube. Now torque the ring caps to 15 inch pounds keeping the same gap from side to side,,you'll have spare feeler gages so you can find one and use it for this.) The feeler gages as the scope is pulled down on them will assure that you have perfectly level reticle. They may be just slightly snug, but should slide out freely when finished. Works like a charm every time.

Hope this helps.

Danny

 

[glo]

I would use the scope installation kit from Wheeler Engineering. I got the kit through Midwayusa.

But the most important thing I have found is a properly bedded base. I think there is a link here on bedded a base but if not here’s how I do it.
1) Torque down the base using one screw in the front hole of the base.
2) If there is no gap between the base and receiver at the rear of the base, go the step 3. If there is a gap measure it with a feeler gage.
3) Remove the one front screw and torque down one screw on the rear hole.
4) If there is no gap between the base and receiver at the front of the base go to step 6. If there is a gap measure it with a feeler gage.
5) If there is a gap between the base and receiver on both ends of the base, the base with the greatest gap is the end in most need of bedding compound,9a). However it would be best to bed both ends. Go to step 8
6) If there is a gap between the base and receiver on rear only, you need only to bed the rear of the base,9b). Go to step 8.
7) If there is a gap between the base and receiver on front only, you need only to bed the front of the base,9c). Go to step 8.
8) Fill both the center front and center rear holes with modeling clay. Place releasing agent liberal on the top of the receiver and somewhat down the sides. Also place releasing agent on the sides and top of the base as well as in the counter-sink areas of the bedded end.
9) Mix you bedding compound,I use Acra-Glas Gel from Brownell’s and color it black) and coat the bottom of the base that had the gap. I try to say a 1/16th of an inch AWAY from the hole,especially when bedding both ends)of the base all the way around. This will help keep the bedding out of the threads.
a. Coat both ends of the bottom of the base.
b. Coat rear end of the bottom of the base.
c. Coat front end of the bottom of the base.
10) Carefully place the base on the receiver right over the holes. *Next put a dab of REALEASING AGENT on the treads of the front and rear screws. Start both screws,not touching the base) for alignment. Torque the screw down that had either no gap or the smallest gap. Final, just tighten the other screw,the big gap end) lightly touching the base. This is again for alignment purposes. You don’t when to load or bend the base.
11) Wipe off the excess that oozes out the sides to make a clean edge.
12) After the bedding compound sets,plastic hard NOT full glass hard) remove the screws and base. Clean of the releasing agent off the receiver and base. The clean out any of the center holes that got bedding compound in them. If the bedding compound is plastic hard you can usually use a knife if not it’s the drill or a dermal.
13) After the bedding compound fully hardens remount the base and torque down the screws in an even manner using the appropriate torque setting.

To mount, align and lap the rings use the instructions from the insulation kit. I found Larry Potterfield on Youtube lapping a set of rings.

It worked for me and I’ve done all my rifles this way. No more do the bullets impact high then low giving me those annoying, vertically, split-up groups.

 

[Dgd6mm]

First bed the base,then go from there.

 

[BMG]

Many thanks for your speedy and detailed replies, I am very greatful.