To Lap or not Lap, that is the question.

[amlevin]

I recently installed a NightForce 12-42X56 NXS on my rifle using all NF hardware. 20 MOA rail/base, and NF Ultralite Rings with Titanium Cross Bolt.

When installing the bottom half of the rings on the rail, torquing the cross bolts, and setting the Scope in the saddle, all seemed to fit well. I didn't have lapping equipment on hand so I just went ahead and finished the install.

Now for the question. Should I revisit the issue of lapping? I'm always interested in wringing the last bit of precision I can from my rifle. What issues would manifest themselves should there be slight alignment issues within the mount? What gain might I realize over just leaving it alone? Because all items are from the same manufacturer is is safe to assume that the setup is pretty close?

All comments welcome.

 

[BoydAllen]

IMO, you never know what you have until you take a few strokes with a lapping bar. I like the Kokopelli bars. Another way to go is to bed the rings. What action ?

 

[fredhorace77]

IMO, you never know what you have until you take a few strokes with a lapping bar. I like the Kokopelli bars. Another way to go is to bed the rings. What action ?

+1 i agree...high quality bases and rings will not correct any issues with the receiver holes...i have seen some receiver mounting holes slightly off and have also seen some actions that were warped slightly..

 

[cncmill]

Not to highjack this post but I too did the same thing and I am rethinking it. The one difference is that I am using a Surgeon action with an 20 moa picatinny rail machined right into the action. Nightforce says it is not necessary to lap but I am rethinking it also.

 

[tunered]

Just dont lap to much, that scope tube should roll in the rings like on bearings.

 

[amlevin]

IMO, you never know what you have until you take a few strokes with a lapping bar. I like the Kokopelli bars. Another way to go is to bed the rings. What action ?

It's a Remington Stainless Action. The mount is a one-piece Picatinney rail and it's bedded to the action with Devcon. Never gave any thought to bedding the rings. I assume you mean the rings to scope tube, right?

I'm beginning to believe that "Devcon can definitely be one's friend" when working with rifles. All my actions are bedded in the stocks with the stuff. Like it so much I'm now on my 2nd one pound container and that's just for MY rifles. 8) 8)

 

[BoydAllen]

Yes

 

[Ing. Michael W. Mayerl]

I recently installed a NightForce 12-42X56 NXS on my rifle using all NF hardware. 20 MOA rail/base, and NF Ultralite Rings with Titanium Cross Bolt.

When installing the bottom half of the rings on the rail, torquing the cross bolts, and setting the Scope in the saddle, all seemed to fit well. I didn't have lapping equipment on hand so I just went ahead and finished the install.

Now for the question. Should I revisit the issue of lapping? I'm always interested in wringing the last bit of precision I can from my rifle. What issues would manifest themselves should there be slight alignment issues within the mount? What gain might I realize over just leaving it alone? Because all items are from the same manufacturer is is safe to assume that the setup is pretty close?

All comments welcome.

A tip: wax the body of the scope - put some epoxy into the rings - put the scope in the rings and torque the srews with 50% of the end force. The epoxy that come out of the rings can be removed with q-tips and alcohol and when its hardened after about 48 hours you fix all screws with 100% torque.

Another tip: the best epoxy is metal filled - it gets very hard.

Nearly all epoxys are oil resistant, they work for decades without any problems. Like the bedding in riflestocks.


Lapping and reaming is not the right way. When there is a big allignment mistake between the front and rear base, it must be repaired by milling or fitting with a file. All bases and base screws should than be glued with epoxy - it give more strength and perfekt fitting. And when you want to remove them you only need to heat it up to about 200°C - very easy.

 

[Sully2]

I recently installed a NightForce 12-42X56 NXS on my rifle using all NF hardware. 20 MOA rail/base, and NF Ultralite Rings with Titanium Cross Bolt.

When installing the bottom half of the rings on the rail, torquing the cross bolts, and setting the Scope in the saddle, all seemed to fit well. I didn't have lapping equipment on hand so I just went ahead and finished the install.

Now for the question. Should I revisit the issue of lapping? I'm always interested in wringing the last bit of precision I can from my rifle. What issues would manifest themselves should there be slight alignment issues within the mount? What gain might I realize over just leaving it alone? Because all items are from the same manufacturer is is safe to assume that the setup is pretty close?

All comments welcome.

MANY builders and assemblers tell you to lap...to use epoxy..to...yadda, yadda, yadda to your rings, etc. Call Leupold and NightForce and see what THEY say. Ive read before than NightForce says NOPE and Ive talked to Leupold and they say NO WAY. I did it on one of the 5 Ive had built in the last year and didnt gain 1 iota...and I wont do it on the 25-06AI Im having built either.

Epoxy belongs where the action meets the stock....not on top of the reciever

 

[BoydAllen]

If a manufacturer tells you to do something that could be viewed as remedial to their equipment, they may feel that it is an admission that the equipment is somehow defective, and if a ham fisted shooter goofs up in the execution, they they might have some culpability for the problem. To my knowledge, scope builders are not proven rifle builders, and if I want advice on building a better rifle, I will go to someone that has made that his business. If you trouble yourself to read Tony Boyer's book, you will see that he makes quite a big deal about how to mount a scope, and I assure you that it is no bolt together deal. Scope manufacturers cannot control the shape of the tops of receivers, or the locations of base mounting holes, and while the parts can generally be screwed together, the outcome when doing so is a marked scope that is under some degree of bending stress.

As to the method of bedding, I would no more tighten cap screws to 50% while the epoxy is setting up, than I would do the same thing with action screws when bedding an action.

One of the best benchrest gunsmiths, Speedy Gonzales told me that he laps to 50% contact, and then beds (rings).

The success of any particular technique depends on the correctness with which it is executed, and frankly there is no way that we can ascertain that from a post.

 

[amlevin]

As to the method of bedding, I would no more tighten cap screws to 50% while the epoxy is setting up, than I would do the same thing with action screws when bedding an action.

I was thinking the same method for holding an action in the stock for a "stress free" bedding job would apply to bedding scope rings as well. Just some surgical tube around the outside of rifle and scope cap with the screws well waxed and used only to align the the caps to the bottom half of the ring. Screws just tight enough to keep the cap aligned, not tensioned.

Just a thought that's been rattling around in my head regarding lapping scope rings.

Are lapping bars and scope tubes both perfect? Perfect enough so that when the rings are lapped that there is NO misalignment? It would seem to my mind that bedding would truly be the only way to make sure that the rings matched the scope tube, and any possible tolerances that might exist in it, when installed on the rifle.

 

[stretch308]

all the scopes ive mounted are on my (and family members) rifles are lapped. i use a sinclair kit. if i swap scopes or rings or whatever i always recheck with the lap bar.as a side note i lap with ring tops in place. i gently snug cap screws as lapping progresses. i aim for 80% contact.

 

[Bert]

Lap or not? I would never put a scope in a set of rings that were not lapped or reamed. I have only lapped the rings i have used. The only purpose of all mentioned techniques is to remove the tolerance of the manufacturing process. The better the rings and bases are and the truer the action is the less likely there is a big error. A friend of a friend asked me to help on a rifle of his. He couldn't get it zeroed at 100yards. after looking at it determind it had a 25 min base. Scope didn't have enough adjustment to do it. Anyway the point of this story when i removed the scope from the high dollar rings it had left rather ugly marks on the bottom of the scope. This guy was sick to his stomach did i mention this was a high dollar scope. So if it marked the scope tube who's fault is that? The ring manufacture? The base manufacture? The scope manufacture? Or the rifle manufacture? A guy could spend a bunch of time trying to figure out what was wrong. Or as some would say wrong. There is nothing wrong. All the pieces just have to be assembled correctly and trued. The key here is trued. Sure you don't have to if you don't mind marks or dents on your scope tube. The best source for info is the guys that shoot the best. They are the ones that have figured out the best way to get all the pieces put together to perform the best. I would be very surprised if there was a top shooter in the country that just drops a scope in the rings and tightens the bolts down. Look at boyds comments he surley is spending time to get everything right.

 

[lpreddick]

i have had some ring/scope fit so bad you could see light shining under the front or back ring/scope "fit". crossbolt rings are a bit easier to get aligned, but if the scope binds the slightest when pushed into the lower ring, there is probably not a good fit. i have lapped some lower rings until the fit was smooth and you could see the lapped portion of the ring. don't like to transfer such rings to other guns. you can use the sinclair lapping tool as a test to see if it binds when pushed into the rings. if the scope sticks when pushed into the rings...i lap.