Can you guys help on what lapping compound to use when lapping an AR upper reciever. I am new to this so any info wound be very helpful. I am putting one together from scratch and piecing together another from spare parts. If someone could walk me through the process, that would be great.
Gunsmithing ? on what lapping compound for AR upper reciever
- Thread starter platapus
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Re: ? on what lapping compound for AR upper reciever
The face on the upper reciever where the barrel nut goes on.
The face on the upper reciever where the barrel nut goes on.
Re: ? on what lapping compound for AR upper reciever
Long tale. I'm pretty sure that a DPMS I have needs it due to longer scopes running out of windage. With all the changing around of parts I will be doing, (3 ar's) I figured I would just lap them all while I was at it.
Long tale. I'm pretty sure that a DPMS I have needs it due to longer scopes running out of windage. With all the changing around of parts I will be doing, (3 ar's) I figured I would just lap them all while I was at it.
Re: ? on what lapping compound for AR upper reciever
I have built over 200 AR and M16's in the last 2 years and I have seen every thing you can do to that gun and this is only done if it is necessary.There are tools made for this operation and you start 600 grit and then move to 1000 for final but i am still not sure that you personally understand why you are doing this. But it really need to be chucked and indicated in a machine to be done properly if done at all or you will cause a much bigger issue.
I have built over 200 AR and M16's in the last 2 years and I have seen every thing you can do to that gun and this is only done if it is necessary.There are tools made for this operation and you start 600 grit and then move to 1000 for final but i am still not sure that you personally understand why you are doing this. But it really need to be chucked and indicated in a machine to be done properly if done at all or you will cause a much bigger issue.
Re: ? on what lapping compound for AR upper reciever
I think he is trying to do this so the barrel doesn't tilt.
I think he is trying to do this so the barrel doesn't tilt.
Re: ? on what lapping compound for AR upper reciever
Yes, i am doing this to eliminate barrel tilt if it is present. I have the lapping tool and upper receiver block. From the limited research I have done, it takes longer to type this out than it does to lap the face.
Yes, i am doing this to eliminate barrel tilt if it is present. I have the lapping tool and upper receiver block. From the limited research I have done, it takes longer to type this out than it does to lap the face.
Re: ? on what lapping compound for AR upper reciever
Well there should be no tilt and if there is that much tilt throwing your scope off then I would seek a different manufacture of upper receiver.The only times I have had a need to do this is a bad receiver or a barrel nut that was improperly installed. And you say you need to do this to 3 of them? I'm currious what is your set up if you don't mind me asking? Gun,scope,rings,bases,barrels.
Well there should be no tilt and if there is that much tilt throwing your scope off then I would seek a different manufacture of upper receiver.The only times I have had a need to do this is a bad receiver or a barrel nut that was improperly installed. And you say you need to do this to 3 of them? I'm currious what is your set up if you don't mind me asking? Gun,scope,rings,bases,barrels.
Re: ? on what lapping compound for AR upper reciever
Well if you have the tools then I would be careful and make sure it's square. But I would use clover lapping compound and start 600 and go-to 800 you should be fine. Use 1000 if high surface finish is desired.
Well if you have the tools then I would be careful and make sure it's square. But I would use clover lapping compound and start 600 and go-to 800 you should be fine. Use 1000 if high surface finish is desired.
Re: ? on what lapping compound for AR upper reciever
I bought a Shilen 1-9" .204, replacing the factory 24" 1-12" barrel to shoot the heavier bullets, the rifle is a factory DPMS. This rifle does not like long scopes (Burris). I ran out of windage with a couple of mount/ring setups. Does absolutely fine with the shorter scopes(Nikon, Leupold).
I am also building a .223 AI w/ a match grade barrel. Last but not least is putting together a .223 out of all the spare parts. I just figured that whle I had the all three tore apart, I would lap the face of the upper receivers. I had read tons of info prior to tearing into these and found that this is one of the little tricks builders use to insure perfect alignment between the upper receiver an the barrel. I just never could find out the grit of the lapping compound.
I don't necessarily need to do all three, just the one. I don't have a lathe or the precision mic gauges to measure how far out of square it is. All I have is the inkling that it needs trued, a hand drill, lapping tool, and the upper receiver block. I hope I don't mess it up. Is there a way to measure it or balance it on end and use a level to see how far out of square it is? Just trying to correct the issue.
I bought a Shilen 1-9" .204, replacing the factory 24" 1-12" barrel to shoot the heavier bullets, the rifle is a factory DPMS. This rifle does not like long scopes (Burris). I ran out of windage with a couple of mount/ring setups. Does absolutely fine with the shorter scopes(Nikon, Leupold).
I am also building a .223 AI w/ a match grade barrel. Last but not least is putting together a .223 out of all the spare parts. I just figured that whle I had the all three tore apart, I would lap the face of the upper receivers. I had read tons of info prior to tearing into these and found that this is one of the little tricks builders use to insure perfect alignment between the upper receiver an the barrel. I just never could find out the grit of the lapping compound.
I don't necessarily need to do all three, just the one. I don't have a lathe or the precision mic gauges to measure how far out of square it is. All I have is the inkling that it needs trued, a hand drill, lapping tool, and the upper receiver block. I hope I don't mess it up. Is there a way to measure it or balance it on end and use a level to see how far out of square it is? Just trying to correct the issue.
Re: ? on what lapping compound for AR upper reciever
It seems to me you would be better off buying a whole new upper. Standarud uppers can be had for $70 and Billet uppers can be had for $140 or less. The tool from Brownells is $35+shipping in addition to the lapping compound you will have to buy. I'm a DIY kind of guy, but if the bolt raceway to tool fit isn't tight, you are likely just pissing in the wind.
It seems to me you would be better off buying a whole new upper. Standarud uppers can be had for $70 and Billet uppers can be had for $140 or less. The tool from Brownells is $35+shipping in addition to the lapping compound you will have to buy. I'm a DIY kind of guy, but if the bolt raceway to tool fit isn't tight, you are likely just pissing in the wind.
Re: ? on what lapping compound for AR upper reciever
I've lapped all kinds of flat stuff using Clover 240 grit, because I like to get the job done quickly. That probably just make somebody shiver, but it does the trick as long as you're not looking for a polished finish (or are trying to obtain a particular clearance between two tightly-fitting parts). Here is a simple guide:
http://www.newmantools.com/clover.htm
Lapping two components together simply ensures that they fit together. It doesn't make them aligned to a datum structure. You would need a fixture to accomplish that goal, or rely upon other receiver features. I'm not sure I'd be relying on any other feature of the receiver if the barrel face wasn't square.
BTW, what does the length of the scope have to do with anything here? Either I'm really stupid and I'm missing something obvious (quite likely), or this is really some other matter (such as how much internal adjustment is provided by the scope).
I've lapped all kinds of flat stuff using Clover 240 grit, because I like to get the job done quickly. That probably just make somebody shiver, but it does the trick as long as you're not looking for a polished finish (or are trying to obtain a particular clearance between two tightly-fitting parts). Here is a simple guide:
http://www.newmantools.com/clover.htm
Lapping two components together simply ensures that they fit together. It doesn't make them aligned to a datum structure. You would need a fixture to accomplish that goal, or rely upon other receiver features. I'm not sure I'd be relying on any other feature of the receiver if the barrel face wasn't square.
BTW, what does the length of the scope have to do with anything here? Either I'm really stupid and I'm missing something obvious (quite likely), or this is really some other matter (such as how much internal adjustment is provided by the scope).
Re: ? on what lapping compound for AR upper reciever
I really don't understand it myself. Two Burris scopes. One 6x18 and one 6x24. One piece mount to the Zee rings w/ inserts. Didn't matter, I ran out of windage. Two Nikon 4x12's and a 4x16 Leupold did fine. That tells me (and maybe I'm stupid) that somethings not true. Whether its the face of the upper or the flat top rail, how the barrel nut is screwed on (looks ok), or what, somethings out of true.
Thanks for the link, I will check it out.
I really don't understand it myself. Two Burris scopes. One 6x18 and one 6x24. One piece mount to the Zee rings w/ inserts. Didn't matter, I ran out of windage. Two Nikon 4x12's and a 4x16 Leupold did fine. That tells me (and maybe I'm stupid) that somethings not true. Whether its the face of the upper or the flat top rail, how the barrel nut is screwed on (looks ok), or what, somethings out of true.
Thanks for the link, I will check it out.
Re: ? on what lapping compound for AR upper reciever
You need to setup and start indicating things to see if they are straight. I wouldn't lap aluminum.
You need to setup and start indicating things to see if they are straight. I wouldn't lap aluminum.
Re: ? on what lapping compound for AR upper reciever
Are your Burris scopes 1/8" per click and the others 1/4"?? Could be you are running out of ajustment because of the limit of adjustment you have?
Just sayin!
Are your Burris scopes 1/8" per click and the others 1/4"?? Could be you are running out of ajustment because of the limit of adjustment you have?
Just sayin!
Re: ? on what lapping compound for AR upper reciever
What rings are you using are they super high?How high is the scope off the gun? I am curious if that may have something to do with it. I ran into this way back with a guy that was legally blind wanting to mount a ATN 65 OBj scope {basically a telescope to a AR} we had to mount that thing so high we were running into adjustment errors. And what distance are you shooting at and what distance will you be shooting at. What is your sight in distance also?
The times I have run out of adjustment on a scope on a AR is with a target scope with fine adjustment and how high they were mounting to the gun. Then they would want to shoot a 25x scope at a 100 yards with super high rings. Or they would try and sight in at 25 yards with the same setup.This will not work on a AR. Or the try mounting the same 25x scope to the handle. But using really high rings accomplishes the same thing.
I would look to this to be a mounting issue not a barrel is not sitting square in the receiver issue.
Hope this helps
What rings are you using are they super high?How high is the scope off the gun? I am curious if that may have something to do with it. I ran into this way back with a guy that was legally blind wanting to mount a ATN 65 OBj scope {basically a telescope to a AR} we had to mount that thing so high we were running into adjustment errors. And what distance are you shooting at and what distance will you be shooting at. What is your sight in distance also?
The times I have run out of adjustment on a scope on a AR is with a target scope with fine adjustment and how high they were mounting to the gun. Then they would want to shoot a 25x scope at a 100 yards with super high rings. Or they would try and sight in at 25 yards with the same setup.This will not work on a AR. Or the try mounting the same 25x scope to the handle. But using really high rings accomplishes the same thing.
I would look to this to be a mounting issue not a barrel is not sitting square in the receiver issue.
Hope this helps
Re: ? on what lapping compound for AR upper reciever
I would be careful hand-lapping something you suspect is out of alignment. Lapping without proper support (chucking in a lathe, some type of trued barrel vise, etc...) for BOTH the barrel and the receiver indicated using the same procedure will only cause more problems.
I would suspect if you hand lap this with the receiver in your left and and the lapping tool in your right that you will only <span style="color: #FF0000">increase </span>the amount of "tilt" on the receiver face.
The correct way to fix this "tilt" problem is to simply chuck the receiver in a 4 jaw on a lathe, true it up (this is the key step) to the bore and face the front until clean.
I would be careful hand-lapping something you suspect is out of alignment. Lapping without proper support (chucking in a lathe, some type of trued barrel vise, etc...) for BOTH the barrel and the receiver indicated using the same procedure will only cause more problems.
I would suspect if you hand lap this with the receiver in your left and and the lapping tool in your right that you will only <span style="color: #FF0000">increase </span>the amount of "tilt" on the receiver face.
The correct way to fix this "tilt" problem is to simply chuck the receiver in a 4 jaw on a lathe, true it up (this is the key step) to the bore and face the front until clean.
Re: ? on what lapping compound for AR upper reciever
I agree completely with the above statement as I said before. But I don't think lapping is going to take care of this issue. i would try to mount the scope as low as you can get it to the gun with out touching the OBJ to the receiver or barrel or hand-guards.
I agree completely with the above statement as I said before. But I don't think lapping is going to take care of this issue. i would try to mount the scope as low as you can get it to the gun with out touching the OBJ to the receiver or barrel or hand-guards.
Re: ? on what lapping compound for AR upper reciever
Like I stated, I first had a one piece mount (Burris) and that failed horribly with the two longer Burris optics. So I switched to a set of Burris high Zee rings with the inserts to corrct the windage. Even w/ the Nikon And Leupold optics, elevation was never the problem, just windage. The rings were the quick fix, now that I will be swapping barrels and such, I figured I would attempt to correct the real issue if I can identify it.
Thanks for your help guys, much appreciated.
Like I stated, I first had a one piece mount (Burris) and that failed horribly with the two longer Burris optics. So I switched to a set of Burris high Zee rings with the inserts to corrct the windage. Even w/ the Nikon And Leupold optics, elevation was never the problem, just windage. The rings were the quick fix, now that I will be swapping barrels and such, I figured I would attempt to correct the real issue if I can identify it.
Thanks for your help guys, much appreciated.
Re: ? on what lapping compound for AR upper reciever
If you have a Reciever block you use to tighten the barrel and your vise is very secure, you could put an indicator on the barrel and see what happens when you tighten the nut. If I am thinking correctly... if it moves .005 at the end of a 24 inch barrel you would be off 3/4 MOA. Please call me out if I am wrong.
If you have a Reciever block you use to tighten the barrel and your vise is very secure, you could put an indicator on the barrel and see what happens when you tighten the nut. If I am thinking correctly... if it moves .005 at the end of a 24 inch barrel you would be off 3/4 MOA. Please call me out if I am wrong.
Re: ? on what lapping compound for AR upper reciever
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Stangfish</div><div class="ubbcode-body">If you have a Reciever block you use to tighten the barrel and your vise is very secure, you could put an indicator on the barrel and see what happens when you tighten the nut. If I am thinking correctly... if it moves .005 at the end of a 24 inch barrel you would be off 3/4 MOA. Please call me out if I am wrong. </div></div>
This sounds good in theory, but in the real world you will never be able to hold the piece rigid enough without some extremely heavy duty equipment and one hell of a strong upper receiver!
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Stangfish</div><div class="ubbcode-body">If you have a Reciever block you use to tighten the barrel and your vise is very secure, you could put an indicator on the barrel and see what happens when you tighten the nut. If I am thinking correctly... if it moves .005 at the end of a 24 inch barrel you would be off 3/4 MOA. Please call me out if I am wrong. </div></div>
This sounds good in theory, but in the real world you will never be able to hold the piece rigid enough without some extremely heavy duty equipment and one hell of a strong upper receiver!
Re: ? on what lapping compound for AR upper reciever
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BigBlue&Goldie</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Stangfish</div><div class="ubbcode-body">If you have a Reciever block you use to tighten the barrel and your vise is very secure, you could put an indicator on the barrel and see what happens when you tighten the nut. If I am thinking correctly... if it moves .005 at the end of a 24 inch barrel you would be off 3/4 MOA. Please call me out if I am wrong. </div></div>
This sounds good in theory, but in the real world you will never be able to hold the piece rigid enough without some extremely heavy duty equipment and one hell of a strong upper receiver! </div></div>
Your probably right but I dont over torque mu uppers any more and I can think of a handfull of ways to check the distortion before and after using a granite inspection block, a pair of v-blocks and a test indicator. Not everybody has access to that kind of stuff though. I wuz just storming. The other part holds water though ehh?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BigBlue&Goldie</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Stangfish</div><div class="ubbcode-body">If you have a Reciever block you use to tighten the barrel and your vise is very secure, you could put an indicator on the barrel and see what happens when you tighten the nut. If I am thinking correctly... if it moves .005 at the end of a 24 inch barrel you would be off 3/4 MOA. Please call me out if I am wrong. </div></div>
This sounds good in theory, but in the real world you will never be able to hold the piece rigid enough without some extremely heavy duty equipment and one hell of a strong upper receiver! </div></div>
Your probably right but I dont over torque mu uppers any more and I can think of a handfull of ways to check the distortion before and after using a granite inspection block, a pair of v-blocks and a test indicator. Not everybody has access to that kind of stuff though. I wuz just storming. The other part holds water though ehh?
Re: ? on what lapping compound for AR upper reciever
Was the original gun you were shooting factory? Where you were running out of windage?
How was it grouping? Did it group well despite a great shift to one side? Or stringing or what?
There's a lot of potential suspects here, including the barrel itself, the barrel nut and how it was torqued and indexed etc.
Was the original gun you were shooting factory? Where you were running out of windage?
How was it grouping? Did it group well despite a great shift to one side? Or stringing or what?
There's a lot of potential suspects here, including the barrel itself, the barrel nut and how it was torqued and indexed etc.
Re: ? on what lapping compound for AR upper reciever
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Beef_Supreme</div><div class="ubbcode-body">Was the original gun you were shooting factory? Where you were running out of windage?
How was it grouping? Did it group well despite a great shift to one side? Or stringing or what?
There's a lot of potential suspects here, including the barrel itself, the barrel nut and how it was torqued and indexed etc.
</div></div>
It is a factory DPMS .204 w/ the 24" stainless fluted. I was running out of windage to the left. With the Nikon And Leupold scopes, the rifle shoots great, 3/4 moa or under.
I've decided to run the lapping tool and see what happens. I would think that after minimal lapping and checking, I wll be able to tell if what I think is the problem exists.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Beef_Supreme</div><div class="ubbcode-body">Was the original gun you were shooting factory? Where you were running out of windage?
How was it grouping? Did it group well despite a great shift to one side? Or stringing or what?
There's a lot of potential suspects here, including the barrel itself, the barrel nut and how it was torqued and indexed etc.
</div></div>
It is a factory DPMS .204 w/ the 24" stainless fluted. I was running out of windage to the left. With the Nikon And Leupold scopes, the rifle shoots great, 3/4 moa or under.
I've decided to run the lapping tool and see what happens. I would think that after minimal lapping and checking, I wll be able to tell if what I think is the problem exists.
Re: ? on what lapping compound for AR upper reciever
If the scope has 60 moa of windage adjustment to one side, that's over 5 feet at 100 yards. That's almost a degree off. You should probably be able to see this much error in the barrel if you put it on a flat surface.
I don't understand why it would happen with some scopes and not others. Why would the scope length make a difference?
Brad
If the scope has 60 moa of windage adjustment to one side, that's over 5 feet at 100 yards. That's almost a degree off. You should probably be able to see this much error in the barrel if you put it on a flat surface.
I don't understand why it would happen with some scopes and not others. Why would the scope length make a difference?
Brad
Re: ? on what lapping compound for AR upper reciever
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JBM</div><div class="ubbcode-body">If the scope has 60 moa of windage adjustment to one side, that's over 5 feet at 100 yards. That's almost a degree off. You should probably be able to see this much error in the barrel if you put it on a flat surface.
I don't understand why it would happen with some scopes and not others. Why would the scope length make a difference?
Brad </div></div>
When I first purchased the rifle in '07 and mounted the Burris, I was immediately out of windage. I tooke the scope of a bolt gun that was dial in with no issues. I sent the scope to Burris and they said it checked out ok and tracked fine. In the mean time while waiting for the scope to return, I mounted another Burris I had laying around. Both were mounted in the Burris P.E.P.R. Low and behold, same issue. I then took a Leupold of another rifle and it worked fine. I put the Leupold back on the rifle it came off of and called Burris. They said that it probably had to due with a combo of the length of the Burris scopes models I had and something not true in the rifle. I then called DPMS and told them the issue. They politically told me the chances were very slim that it was an issue with their product. Burris by the way sent me free of charge a set of high Zee rings w/ the inserts which was very awsome CS. So next I purchased a Nikon and put it on the rifle with no issues.
From my earlier posts, you are aware that I bought a 24" Shilen and will be swapping barrels. I have done quit a bit of research tracking down what the problem could be. I am pretty sure that the face of the upper reciever is not true. I do not want to have the same issues with the Shilen. I bought a lapping tool, barrel nut wrench, and the block for the upper receiver. I am confident that after just few slow rotations and checking the receiver face, I will be able to tell if one side is lapping or if its not.
On another site, a guy was having major grouping issues and did what i'm about to do an changed the rifle to a good shooter. This is worth the try to me. If I screw it up, I will come clean and you guys can tell me "I told you so".
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JBM</div><div class="ubbcode-body">If the scope has 60 moa of windage adjustment to one side, that's over 5 feet at 100 yards. That's almost a degree off. You should probably be able to see this much error in the barrel if you put it on a flat surface.
I don't understand why it would happen with some scopes and not others. Why would the scope length make a difference?
Brad </div></div>
When I first purchased the rifle in '07 and mounted the Burris, I was immediately out of windage. I tooke the scope of a bolt gun that was dial in with no issues. I sent the scope to Burris and they said it checked out ok and tracked fine. In the mean time while waiting for the scope to return, I mounted another Burris I had laying around. Both were mounted in the Burris P.E.P.R. Low and behold, same issue. I then took a Leupold of another rifle and it worked fine. I put the Leupold back on the rifle it came off of and called Burris. They said that it probably had to due with a combo of the length of the Burris scopes models I had and something not true in the rifle. I then called DPMS and told them the issue. They politically told me the chances were very slim that it was an issue with their product. Burris by the way sent me free of charge a set of high Zee rings w/ the inserts which was very awsome CS. So next I purchased a Nikon and put it on the rifle with no issues.
From my earlier posts, you are aware that I bought a 24" Shilen and will be swapping barrels. I have done quit a bit of research tracking down what the problem could be. I am pretty sure that the face of the upper reciever is not true. I do not want to have the same issues with the Shilen. I bought a lapping tool, barrel nut wrench, and the block for the upper receiver. I am confident that after just few slow rotations and checking the receiver face, I will be able to tell if one side is lapping or if its not.
On another site, a guy was having major grouping issues and did what i'm about to do an changed the rifle to a good shooter. This is worth the try to me. If I screw it up, I will come clean and you guys can tell me "I told you so".
Re: ? on what lapping compound for AR upper reciever
I never said you didn't have a problem, but if the barrel is off that much, you should be able to see it. Of course, since the rifle is OK with other scopes, I would look at the scope itself and the mounts. I can't imagine how much metal you would have to lap off to make the barrel straight -- and if you did, it would probably be so loose that it would be dangerous to shoot.
Of course, it's not my rifle, so please post pics -- I'm curious.
I never said you didn't have a problem, but if the barrel is off that much, you should be able to see it. Of course, since the rifle is OK with other scopes, I would look at the scope itself and the mounts. I can't imagine how much metal you would have to lap off to make the barrel straight -- and if you did, it would probably be so loose that it would be dangerous to shoot.
Of course, it's not my rifle, so please post pics -- I'm curious.
Re: ? on what lapping compound for AR upper reciever
From their responses, I suspect that some of those responding to this thread haven't seen the lapping tool you're talking about. Since it has a shank that fits tightly in the place of the bolt carrier to keep the tool straight, you don't need a fixture or a lathe. I know several custom or semi-custom builders that use one to true every rifle they build.
I'm not a gunsmith, but I use valve lapping compound from the local auto parts store for my lapping needs, it works fine.
From their responses, I suspect that some of those responding to this thread haven't seen the lapping tool you're talking about. Since it has a shank that fits tightly in the place of the bolt carrier to keep the tool straight, you don't need a fixture or a lathe. I know several custom or semi-custom builders that use one to true every rifle they build.
I'm not a gunsmith, but I use valve lapping compound from the local auto parts store for my lapping needs, it works fine.
Re: ? on what lapping compound for AR upper reciever
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Red_SC</div><div class="ubbcode-body">From their responses, I suspect that some of those responding to this thread haven't seen the lapping tool you're talking about. Since it has a shank that fits tightly in the place of the bolt carrier to keep the tool straight, you don't need a fixture or a lathe. I know several custom or semi-custom builders that use one to true every rifle they build.
I'm not a gunsmith, but I use valve lapping compound from the local auto parts store for my lapping needs, it works fine.
</div></div>
That's the lapping tool and compound I'll be using. Barrel wrench hasn't showed up yet. I'm only home everyother weekend so it looks like this task is out on hold until I come home again.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Red_SC</div><div class="ubbcode-body">From their responses, I suspect that some of those responding to this thread haven't seen the lapping tool you're talking about. Since it has a shank that fits tightly in the place of the bolt carrier to keep the tool straight, you don't need a fixture or a lathe. I know several custom or semi-custom builders that use one to true every rifle they build.
I'm not a gunsmith, but I use valve lapping compound from the local auto parts store for my lapping needs, it works fine.
</div></div>
That's the lapping tool and compound I'll be using. Barrel wrench hasn't showed up yet. I'm only home everyother weekend so it looks like this task is out on hold until I come home again.
