Does lapping scope rings assure scope alignment and improve group size?

[GSPV]

Anyone ever seen their point of impact walk on a bright sunny day? I used to.

 

[Raythemanroe]

Anyone ever seen their point of impact walk on a bright sunny day? I used to.

Is that mirage and burn rate more so then holding point of impact?

 

[BoydAllen]

A friend did an experiment that relates to your question. He measured the distance between the inside of his scope ring caps, and then set the rifle in the sun for a half hour, and then remeasured it. The distance increased by several thousandths. He told me that if he is doing some serious testing, that after the rifle is warmed up he slightly loosens the rear ring on the scope, and then retightens it. Short answer, he has observed a change in point of impact.

 

[BigDMT]

A friend did an experiment that relates to your question. He measured the distance between the inside of his scope ring caps, and then set the rifle in the sun for a half hour, and then remeasured it. The distance increased by several thousandths. He told me that if he is doing some serious testing, that after the rifle is warmed up he slightly loosens the rear ring on the scope, and then retightens it. Short answer, he has observed a change in point of impact.

Very good info

 

[GSPV]

Anyone ever seen their point of impact walk on a bright sunny day? I used to.

Is that mirage and burn rate more so then holding point of impact?

Nope. Friend's 22 RF ammo testing rail gun. Groups didn't open. POI walked. Admittedly, it was an Alabama-type bright, sunny, hot day. But the POI observably walked.

 

[Raythemanroe]

Interesting!

 

[GSPV]

It's worth knowing.

It's worth an ounce of prevention. If nothing else, throwing a towel over your rig when you're not shooting is worth something.

People don't appreciate how much the sun can heat things up. On a relatively cool, but bright morning, I've had empties on the bench heat up till they were uncomfortable to hold. Think what that'd do if they were loaded rounds and got all nice and hot... I have to think that it'd change something.

 

[Redd]

The fellow that I used to work for, has a much bigger rifle and scope budget than I do, and since I was the one that introduced him to some of the finer points of rifle building, shooting and reloading, it fell to me to mount his scopes. Let me tell you, when you are mounting scopes that retail for more than 2,000, for the fellow that signs your check, you want to get it right the first time. The rings were top of the line, and the scope bases were integral or one piece. I used Kokopelli lapping bars and the compound that is furnished with them. The story is told when you take a few strokes with the charged bar, and then look at the cutting pattern in the bottom halves of the rings. In every case, the fit was improved by lapping. None of this guarantees the alignment of the scope, that is determined by the alignment of the action's base mounting holes. The actions that we were working with were all custom and pretty well aligned, based on the amount of adjustment it took to zero the scopes, starting with the reticules centered. I have also bedded rings with good results. The easiest solution to date, when weight is not critical is to combine a Weaver spec. base or bases, with Burris Signature Zee rings. With these rings and the proper pairs of offset inserts, minor miracles can be accomplished. I have a Savage rifle that required .020 offset inserts, installed with the offsets aligned horizontally, with the front in the opposite direction from the back, to center the scope on the action. The combination worked very well, bringing the scope very close to perfect alignment, with no lapping, bedding or any sort of metal work. Obviously actions should not be this far off, but this one is, and I was able to fully compensate for the misalignment. Lots of fellows are told that you can buy the expensive stuff and just bolt things together. If you are dealing with factory actions this is complete BS, and even with custom actions, it is better to either lap or bed. As to whether you will see any difference on the target, it is hard to say. That depends on how correct other details are, including the rifle, scope, loads, and the shooter.

And if you see no improvement in accuracy then the entire point is moot!

 

[dolek]

And if you see no improvement in accuracy then the entire point is moot!

You brought this thread that went dead in 2013 back to life just to throw that negative comment out there ?

 

[Redd]

You brought this thread that went dead in 2013 back to life just to throw that negative comment out there ?

Bored.

 

[Surfgent]

I've never lapped a scope

 

[jaytee]

Just curious, if heat is such an issue, why are scopes finished in black instead of another color that would reflect heat instead of acting like a sponge?

 

[searcher]

Truing the rings and bedding the scope does for the optics what bedding the action to stock does to the rifle. If one wants to eliminate one more variable to accuracy - this is a good thing to do. Best to remove uneven stresses on any parts of a rifle if they can be reasonably eliminated.

 

[BoydAllen]

I've never lapped a scope View attachment 1172170

Even if I did not believe that there would be an accuracy improvement, I would lap, just to make sure that I did not have ring marks. I like aluminum rings, and they are easy to lap. BTW, what exactly was the point of the target?

 

[Hohn]

Lapping scope rings neither assures absolute alignment nor reduces group size as a matter of certainty.

It can assure that the two rings are aligned to each other. But it cannot assure that this axis is also aligned to the action or to the bore.

It is also a poor means of correcting for action holes that aren’t well positioned.

Lapping is mostly a holdover from when rings were directly mounted to the action, usually by a smith who could not control true position of the holes very well, so lapping was helpful to compensate for that. Also, the poor positioning would cause the scope tension to deflect the action and lead to unexplained flyers.

But with a modern scope mounted on a precision base (a 1pc base or a cnc machined action) there’s is so little value it’s not worth bothering to do.

 

[Surfgent]

Even if I did not believe that there would be an accuracy improvement, I would lap, just to make sure that I did not have ring marks. I like aluminum rings, and they are easy to lap. BTW, what exactly was the point of the target?

I guess to show what kind of results I was getting and giving my 2 cents on the subject. After all isn't that the point of having the forum and electronically talking with each other about it. But judging from some of the feedback I guess that's a unacceptable terrible group. I dunno looked good to me, I also had a guy on hear tell me because I was using PPU Serbian brass and bullets and not nosler lapua Sierra or norma that I was some kind of a amateur and spinning my wheels and wasting my time and $. But like I said I'm happy with my results.

 

[BoydAllen]

Back when I started reloading, it was for an inexpensive 788 Remington, using a Lee Loader and a plastic mallet, with all sorts of different brass, none of it the brands you mentioned. All of it came from the cheapest loaded ammo that was on the shelf. The s cope and rings were the cheapest made, a bottom line 4x Tasco, and some flimsy rings, unlapped of course. I had a lot of fun back then, as much as I do now with a lot of fancy rifles, loading gear, brass and bullets. Perhaps I should not have mentioned the target, but is was my way of giving a strong hint that for many viewers it did not show what you intended it to. Back in those days, my typical groups were under an inch, with the best running about 5/8 all five shots. At the time I was totally clueless about proper scope mounting, including lapping. That was the first rifle that I floated the barrel, and bedded the action. All of my powder charges were done with the single dipper that came with the loader, using one or more of the suggested powders. I did not even own a scale. It was all brand new to me, and I had no one to learn from. It was all cut and try.

 

[searcher]

I also had a guy on hear tell me because I was using PPU Serbian brass and bullets and not nosler lapua Sierra or norma that I was some kind of a amateur and spinning my wheels and wasting my time and $. But like I said I'm happy with my results.

I truly think Lapua and Norma brass are superior to pretty much anything else out there in respect to overall quality and durability. That said - phenomenal groups can be had shooting brass that is routinely described as "garbage" by a lot of folks. I shoot Lapua and Norma exclusively in my target rifles and couldn't be happier with the stuff. That said - some of my best groups ever fired came from Federal .308 brass I had converted to .243 back in the brass shortage. Granted - a lot of prep work was done to the brass. But what is most important is what you just said - whether YOU are satisfied with it.

 

[Surfgent]

I truly think Lapua and Norma brass are superior to pretty much anything else out there in respect to overall quality and durability. That said - phenomenal groups can be had shooting brass that is routinely described as "garbage" by a lot of folks. I shoot Lapua and Norma exclusively in my target rifles and couldn't be happier with the stuff. That said - some of my best groups ever fired came from Federal .308 brass I had converted to .243 back in the brass shortage. Granted - a lot of prep work was done to the brass. But what is most important is what you just said - whether YOU are satisfied with it.

Yes I agree. I have the premium stuff and it shoots great also the cheap stuff almost as well. I think this is the beauty of reloading