Lapping

[NightStalker]

Has anyone lapped an Aero precision enhanced upper?

 

[98Z5V]

Nobody here has shown any pics of it yet, for sure.  As far as I know, there is only one company that makes a tool that will do that job. 

https://www.gandgrifleworks.com/AR10-Lapping-Tool-p/arlapset.htm

Edited December 15, 2019 by 98Z5V

[NightStalker]

Thanks for the reply, I found a video on YT by accident on this subject and G and G RW tool, it didn’t show the process which is what I was looking for to determine how far out of square it was. I guess just Lapp it it can’t hurt

[jtallen83]

10 minutes ago, NightStalker said:

to determine how far out of square it was.

You can see how square it is as soon as you start lapping. Hit it a little and look at the shiny spots, if it is even all the way around then its square.

[98Z5V]

13 hours ago, NightStalker said:

Thanks for the reply, I found a video on YT by accident on this subject and G and G RW tool, it didn’t show the process which is what I was looking for to determine how far out of square it was. I guess just Lapp it it can’t hurt

Alot of people think you need to chuck this thing up in a drill, and get after it.  I do it by hand, no drill, turn it by hand with slight pressure, and look at it after a few turns.  See what I'm getting, see what I need...  Repeat until I have a fine silver circle all the way around. Several beers are required, on a calm night, but they all work out perfect that way, nothing is over-ground.  Most QUALITY uppers these days don't require hardly anything at all on them, and they're good right out of the gate. You could leave them alone, and it wouldn't matter.  My $0.02.

[jtallen83]

7 hours ago, 98Z5V said:

Most QUALITY uppers these days don't require hardly anything at all on them, and they're good right out of the gate

I have not found that, Aero and Matrix needed a good bit. Anderson has need some work, and two DPMS were just horrible. The only one I have had good from the start was a Vltor. This is both platforms. 

[mrmackc]

Look and ye shall find. . . . .sometimes more than you should have found, makes for a mess of stress.

[NightStalker]

Has anyone lapped the enhanced upper from Aero though, I’ve lapped uppers just not this upper

[COBrien]

On 12/17/2019 at 7:12 AM, jtallen83 said:

I have not found that, Aero and Matrix needed a good bit. Anderson has need some work, and two DPMS were just horrible. The only one I have had good from the start was a Vltor. This is both platforms. 

Same story here.

My Fulton Armory .308 upper was pretty good out of the box -- didn't take much lapping.
2 Fulton AR-15 uppers were okay.
A no-name Cerro Forge AR-15 upper was comparable to the FA AR-15s.

The upper I've had that needed the most lapping was an Aero M5 (not E1). First pass revealed a high spot over about 1/4 of the circumference, and it took quite awhile to get her evened out.

[SgtDog0311]

I did a first pass on an M5E1 night before last.   The G&G lapping compound included with the tool was 120grit and felt like gravel so I stopped and cleaned and am ordering some 220 grit.   Now this was my first of any kind so take that for what it's worth.    The little I exposed in the (hand) lapping looked to be fairly uniform though a short stretch looked like there was less exposure.  Since I pulled off it early and didn't expose much I may find this misleading when the 220 grit arrives. 

Btw, my Criterion Barrel Extension made a decent fit so not sure what I'll do about bedding.   I don't have tools to measure the delta between the barrel extension OK and the inside diameter of the barrel nut.   But without a barrel nut on at all the barrel itself is a little difficult to pull off.

Lapping these M5E1s seems like a whole other animal from a typical receiver extension if that makes any sense.    And of course I'm seeing it from having a hands-on with the M5E1 and only videos to watch with the M5. 

[jtallen83]

21 hours ago, COBrien said:

My Fulton Armory

I forgot about that, lapped one of their receivers for the brother in law. It was good to go, basically just leveled out the cerakote and it was good. 

[SgtDog0311]

NightStalker,  I'd be interested in comparing notes if you proceed with yours.   The way I see it, and again, confessing little-to-no-experience, there is a big difference in how you'd want to handle the M5 and M5E1.   Not so much in the lapping, though I do wonder there if it wouldn't be best to orient vertically rather than horizontally in the vice as I hand-turn.   I'll know more once my 220 grit arrives.  But the big difference I envision is in the bedding.   With the exposed receiver extension of the M5, you have the opportunity to wipe off excess as it squeezes out over the raised flange of the extension.   Whereas with the shrouded nature of the M5E1 that excess is going to squeeze out where it can't be reached very well, possibly as far as the female threads of the Enhanced integral Free-float fixture, and even run into the interface between the outside surface of the barrel extension flange where the barrel nut will apply torque.    I've got about .0035 of tolerance and how to apply just the right amount of bedding on that surface in order to minimize excess squeezing out is my question/concern.    

[unforgiven]

Has anyone done a before and after ?  Has anyone seen a degree of improvement to warrant this process ? 

Just wondering...or are you doing it just to do something ?

[SgtDog0311]

Not sure if that question is for the OP or just anyone in general.    
 

For me, I’ve seen enough thru a lot of searching to convince me of the utility to at least check if the face is square.    My plan is to check frequently while lapping to see, looking for even or uneven wear.   If it’s evenly wearing I’ll stop as soon as signs are visible.    
 

As for the bedding, it makes good sense.   But more than that it’s recommended by a great deal of precision shooters and performed in one way or another, (heat fit, shims, loctite or fitted bat barrel extensions) by precision builders and armorers for competition teams.    
 

That said, its probably an excellent question for each to answer for his rifle.   I’ve seen it asked and answered elsewhere.    Some claim it shrinks groups by as much as a 1/3rd.   But only shooting a before and after would answer for each instance.   I considered checking for flat/square then shooting before bedding.    Have not decided yet.

[NightStalker]

I can see squaring the receiver and has seen my Aero Ar15 was out a little bit when i built it, but not sure about bedding a barrel. I have not read or seen anything that would make me think a good quality barrel needed bedding. I have put moly grease or antisieze on the barrel and nut but mainly to be able to tear it back down and a future date   

This is just my opinion only guys

 

Edited December 26, 2019 by NightStalker

[unforgiven]

It's an open question.. thanks guys

[98Z5V]

"Bedding the barrel" on an AR with a free-float handguard consists of using Loc-Tite 609 around the barrel entension, to secure it in the upper receiver.  That's all it is. 

Here's Loc-Tite 609:

High strength methacrylate ester acrylic retaining compound designed for the bonding of cylindrical fitting parts.

LOCTITE® 609 is a green, high strength methacrylate ester acrylic retaining compound designed for the bonding of cylindrical fitting parts. The product cures in the absence of air between close fitting metal surfaces. Typical applications include rotor to shafts in fractional and subfractional horsepower motors. Locks bushings and sleeves in housings on shafts. Augments press fits.

• Low viscosity
• Prevents loosening and leakage from shock and vibration
• Augments press fits
• Tested to the lot requirements of Military Specification Mil-R-46082B (this is a regional approval)

[jtallen83]

11 hours ago, NightStalker said:

I have not read or seen anything that would make me think a good quality barrel needed bedding.

I have used the 609 on the extensions of all the rifles I have built now. There were a few that were up and running beforehand but most are done from the go. Those that were retrofit didn't show it as a miracle cure for large groups BUT none showed any negative. I have tore down a couple that it was used on and had no issues. 

For me using the 609 is more a confidence booster, one less thing to wonder about. Considering all the other things that are done in the name of accuracy bedding the extension with 609 is low hanging fruit, so easy to snag it on the way by.

[SgtDog0311]

Unforgiven, or anyone,    If you are interested here is a short video that purports to go back to the 'cause that found a remedy'.     Anyway, the gunsmith for the team didn't seem to have any prior knowledge/experience with it.   

The gentleman is the former chief gunsmith of the USAR team as well as a world record holder.   He writes, or did, for the American Gunsmith magazine, which in my world almost qualifies him as a suspect, but I read a few of his articles and he didn't appear to be just another marketing mouthpiece to me.   

Now... I did exchange some emails with him and he did have an experience with AERO and opinions on uppers I can't get a vector check on.   

Personally I'm intrigued by JP's "heat-shrink" process.   Not saying I'd do it but dang...  doesn't even look like they use a barrel nut.  Maybe they do but didn't look like they spun one on in their video.    Now that I put that in black in white... surely they do.  Not using it would be an insane liability.   

Oh, also of possible interest to you, this guy further tunes harmonics (ammo specific) with barrel nut torque.      

[SgtDog0311]

JT,  maybe I missed it but have you done a AERO Enhanced?   I ask because I really am bothered a bit by that "excess" issue down inside their fixture.   

btw, I've been in another discipline and remain in that camp (at least as long as my Glaucoma is held in check) despite my interest here but everything I've learned there tells me this is a no-brainer.   But here is the kicker... you go to another venue like this and you run into the same thing you do anywhere.    There are internet gurus and then there are the guys you are trying to assess for trustworthiness.   So, here I order a Criterion and I have a few exchanges there and the word I get is "start over" concerning the Enhanced and go back to the M5.   Dang, that one threw me for a loop since it was that free float fixture that caught my imagination and got me off the fence finally about building a 308.    Go figure, right!

[SgtDog0311]

And for those who have, here is a thought I'd had for limiting that 'excess' squeezing out:   I thought perhaps that could be minimized by using a piece of card stop or something to ensure the film of bedding, whatever you used, was spread very thin and uniform on the extension in order to limit the excess being squeezed out down in that recess.     I ruled out using shim stock since I only have about three thousands tolerance - I thought working that extension in there with a 1 thousands shim wrap would really be a bear.

[unforgiven]

So I take it, this direction is a target rifle build not an average assembly. Curious to see how your end product compares to a stock box  M5.

[SgtDog0311]

I share your curiosity unforgiven, I surely do, especially being my first build.   I've got an M1A and an AR but I shoot about 16 matches a year in BPCR and BPTR so that's where I spend most all my time.    While it's not bench rest its precision in a sense.    And shooting my own cast bullets, of my own bullet design and my own load work, anywhere from 200 to 800yds for score, even in 135 yr old rifles, leaves me disposed towards the best accuracy I can get.   Honestly I bet I'd be the same if I was hunting hogs at 150yds:-)     

Regarding the 'stock box'.  I was tempted.   But I usually immerse myself and thought a build would be best for knowing the rifle.   I think I'm right about that but I'm making no claims about a novice's ability to exceed some of those better regarded turn-key rifles out there.

[jtallen83]

2 hours ago, SgtDog0311 said:

JT,  maybe I missed it but have you done a AERO Enhanced?

Sorry, should have clarified, just a proponent of doing it when you can, no enhanced in hand. Give it a go on the enhanced, just start out on the light side and see how it looks.

[unforgiven]

1 hour ago, SgtDog0311 said:

I share your curiosity unforgiven, I surely do, especially being my first build.   I've got an M1A and an AR but I shoot about 16 matches a year in BPCR and BPTR so that's where I spend most all my time.    While it's not bench rest its precision in a sense.    And shooting my own cast bullets, of my own bullet design and my own load work, anywhere from 200 to 800yds for score, even in 135 yr old rifles, leaves me disposed towards the best accuracy I can get.   Honestly I bet I'd be the same if I was hunting hogs at 150yds:-)     

Regarding the 'stock box'.  I was tempted.   But I usually immerse myself and thought a build would be best for knowing the rifle.   I think I'm right about that but I'm making no claims about a novice's ability to exceed some of those better regarded turn-key rifles out there.

I got you now brother you have a higher degree of skill than the average person. That's great 😊