Lapping for accuracy

[Allen Roberts]

Guys if you’re pretty satisfied with shooting 1” moa at 100yds should I lap my receiver trying to squeeze a little more accuracy out? I don’t want a big chance of doing damage.

[FRB6.5]

If you are shooting 1 MOA and don't have gross windage or elevation corrections you likely don't need to lap. Bedding/shimming may help depending on your current fit.

[A5BLASTER]

Lapping is for a square bolt lock up.

Bedding is for group size.

[Allen Roberts]

I believe you A5B. Just tell the other 40 percent of shooters say bolt barrel marriages improve accuracy and 85 percent of the shooters out there say lapping the upper improves accuracy or better groups if we are talking about the same reason.

[A5BLASTER]

I believe you A5B. Just tell the other 40 percent of shooters say bolt barrel marriages improve accuracy and 85 percent of the shooters out there say lapping the upper improves accuracy or better groups if we are talking about the same reason.

I'm not really worried about the other's. My testing is enough to proof to me that lapping is for a square bolt lock up and bolt life and bedding if for accuracy.

I think most people who say that lapping the reciver made the gun shot better, had some other issue and didn't know it and fixed it without knowing it and then turn around and account it to lapping the reciver.

[lazyengineer]

I'm not really worried about the other's. My testing is enough to proof to me that lapping is for a square bolt lock up and bolt life and bedding if for accuracy.

I think most people who say that lapping the reciver made the gun shot better, had some other issue and didn't know it and fixed it without knowing it and then turn around and account it to lapping the reciver.

That's what I think.

[Klem]

I can see the benefit of lapping, or squaring the receiver to the barrel. If the barrel is pointing in a different direction to the scope then the size of the group [precision] will not be affected but the ability to predict and drive this group around the target [accuracy] will be. This is more noticeable the further the target is from the shooter.

I understand bedding to be an attempt to fix a sloppy fit between barrel and receiver by introducing more rigidity. Presumably, more rigidity will influence precision and in theory this makes sense. Whether bedding actually does improve precision in an AR is not universally agreed. In a bolt gun it is.

One is guaranteed to improve the guns performance while the other probably does, especially if the interface is sloppy. Or, you can get a tight fit to start with. I have tried gluing and it did not improve group sizes. Others however have found that it helps and swear by it.

[Allen Roberts]

I gather and study every answer l read. If you feel lapping is beneficial, then do it. Same idea breaking in a barrel. Some people think it’s a waste of time. Keep the information coming. Thanks.

[Klem]

Allen,

Breaking-in a barrel is another contentious topic. I used to religiously spend an afternoon breaking in new barrels with shooting and cleaning, shooting and cleaning - I don't anymore. If there was any benefit to it I never saw it.

Top tier barrels like Krieger and Lilja come ready to shoot. The first few rounds fill the micro pores with copper which I deliberately don't remove. It has been years since I used copper cleaners like Sweets and Bore Tek. I noticed when you strip the bore of everything the next time you shoot is spent fouling and settling the barrel back into where the MPI was before you cleaned it. Now, I often just put the gun straight back in the safe with a length of anti-corrosion cord down the bore, no cleaning the bore. I still clean the carbon out with Butch's every now and then when the groups seem to be opening up but that's about it. The action gets cleaned every time, just not the barrel.

[Allen Roberts]

Klem, l generally pass two #9 patches, followed by a couple of dry patches maybe with a shot of ballistol. Looks like I’am still cleaning too much. So no cleaning until the group opens up?

[Klem]

Allen,

For years I was institutionalized with the military dogma of having to clean every time a firearm is used and even when not used but idle for a long time. There's a good reason for doing this but it is still dogma, and a lot of the time, unecessary. As an individual however you do what's best for you. I started reading about guys not cleaning and also spoke with a gunsmith who said that cleaning is in the best interests of barrel makers - they wear out quicker (although I don't place much credibility on that if you are using soft brass brushes on steel). I also saw a barrel that had been cleaned so much with one side being biased by the way the guy pushed the rod through that it wrecked it.

If you are comfortable you have corrosion in check while the gun is in storage then why not give it a go. Keep a tally of group sizes and MPI and see the difference between cleaning and not cleaning between a shooting session. If nothing has changed the next time you pull it out then let it go another session, and so in until you see a change, or can't stand it anymore.

[lazyengineer]

Allen,

Breaking-in a barrel is another contentious topic. I used to religiously spend an afternoon breaking in new barrels with shooting and cleaning, shooting and cleaning - I don't anymore. If there was any benefit to it I never saw it.

Top tier barrels like Krieger and Lilja come ready to shoot. The first few rounds fill the micro pores with copper which I deliberately don't remove. It has been years since I used copper cleaners like Sweets and Bore Tek. I noticed when you strip the bore of everything the next time you shoot is spent fouling and settling the barrel back into where the MPI was before you cleaned it. Now, I often just put the gun straight back in the safe with a length of anti-corrosion cord down the bore, no cleaning the bore. I still clean the carbon out with Butch's every now and then when the groups seem to be opening up but that's about it. The action gets cleaned every time, just not the barrel.

Klem I'm glad you posted this.

This has been my experience as well, and at times I wonder if the old conventional wisdom on such was still quite so relevant today. Today's modern machining, metallurgy, powder technology, and jacket technology; I'm just not experiencing much benefit to frequent cleaning, and often think it works against me, as it seems like it takes a few rounds (or strings even), to settle back down.

[FRB6.5]

@Klem link to the anti-corrosion cord material you use? Not heard of this and sounds super interesting.

[Klem]

@Klem link to the anti-corrosion cord material you use? Not heard of this and sounds super interesting.

https://www.zerustproducts.com/products/...be-strips/

I'm paranoid I am going to forget it's there one day so I tie a big knot in the end - it sticks out like a chamber flag.

[FRB6.5]

Thanks Klem! I've used their bags but had no idea this even existed.

[FLshooter]

I started lapping my barrels because I saw my buddy at the tactical shop do it. Never noticed an improvement in accuracy but it does give the barrel a square fit. I’ve also seen people bed AR barrel using green or red Loctite and I’ve done for others . I won’t do it for myself, because I’ve never seen enough evidence to prove that it helps with accuracy.
If you want guaranteed accuracy you need to start with a quality barrel. I like Bartlein barrels.And I’ve been upgrading all my AR’s with custom Bartlien barrels from Craddock Precision.So far, every barrel I’ve swapped out is a sub MOA shooter.
as far as breaking in a barrel, I grew up hanging around in my uncles hunting and fishing shop in New Haven Connecticut. If I had a dime for every time I heard him give break in advice to a customer purchasing a new hunting rifle, I’d be a millionaire.
His advice was run patches through barrel every 10 rds for first 100 . Then clean it regularly. I did this for a long time.Then I just went to cleaning all my barrels ,new or old after every range session or 100 rds.I run a nylon brush to loosen carbon. Then I run patches down the barrel till they come out clean. Never noticed a difference either way.

[NightStalker]

I dont know if it is more accurate, but to me it makes sense to lap the receiver. The first one i did i was amazed at the process and as the receiver polished up and squared off little by little i can see how in theory it trued up the barrel to receiver

[Allen Roberts]

Klem, finally some good news. The last two times I have shot less les than 1” moa at 100yds. With Hornady eld-m123gr.,federal fusion 120gr., and Barnes vortex tx 115 gr( hard to find). Fiottchi has never come close to grouping with any of my guns. I have been wearing a patch over my left eye and I feel like the gun just settled in. I did change the gas block and tube, changed my set up, and worked on ammo. Almost after a few rounds, the groups suddenly tightened up. Maybe some of all of it helped. Thanks for your help and everyone else. We still live in the greatest country of the world.

[Allen Roberts]

Fiocchi spelling correct. My apology.

[Klem]

Allen,

That sounds like good news.

What Fiocchi ammunition are you referring to?