True and Glue Before and After PSA-65

[Juggerxxx]

As of posting this thread I only have data for the before. I hope to be done truing and gluing and firing three more 5 shot groups for both the 147ELD and 140ELD in the next couple of weeks. Not sure if it will make it shoot better, the same or even worse. The cheap gas gun seems to like 147ELD and shoots it fairly well. Both are hand loads and they will be shot from the same batch. I did measure about 0.0005” height difference on one side of the receiver face.

 

[Yondering]

Just curious why you chose Loctite 609?

609 will work, but I've recommended 680 for this job on the forum a bunch of times for a couple reasons - it's higher strength, tolerates minor oil contamination, and cures in a larger air gap (less important, the air gap is small enough for both products, but it's more versatile for other uses like scope bases).

See differences here:
609: https://www.henkel-adhesives.com/us/en/product/retaining-compounds/loctite_609.html

680: https://www.henkel-adhesives.com/us/en/product/retaining-compounds/loctite_680.html

 

[Juggerxxx]

Just curious why you chose Loctite 609?

609 will work, but I've recommended 680 for this job on the forum a bunch of times for a couple reasons - it's higher strength, tolerates minor oil contamination, and cures in a larger air gap (less important, the air gap is small enough for both products, but it's more versatile for other uses like scope bases).

See differences here:
609: https://www.henkel-adhesives.com/us/en/product/retaining-compounds/loctite_609.html

680: https://www.henkel-adhesives.com/us/en/product/retaining-compounds/loctite_680.html

Thank you for the suggestion Sir! I will pick some of the 680 up instead. Have you even done a comparison before and after and if so did it ever make groups, consistency or POA worse?

 

[bfoosh006]

In for your results.

My "test" showed my PSA barrel responded well to the TnG.

Firing more Factory rounds into much better group sizes.

Big difference in the before and after on those rounds.

I will IM you a link so as not to "crowd" this thread.

Please note... while some groups appear "worse" ... that could be just having a "bad" day shooting tight groups... Lol.. to many cigs or to much coffee.

 

[Juggerxxx]

In for your results.

My "test" showed my PSA barrel responded well to the TnG.

Firing more Factory rounds into much better group sizes.

Big difference in the before and after on those rounds.

I will IM you a link so as not to "crowd" this thread.

Please note... while some groups appear "worse" ... that could be just having a "bad" day shooting tight groups... Lol.. to many cigs or to much coffee.

I completely understand a bad day where groups just don’t group for some reason. Feel free to clutter this thread I seriously have zero issue with it. If it’s good info I believe it’s important to share data. Don’t forget; your the whole reason I’m jumping head first down this true and glue Rabbit Hole!!!!!!!!

 

[Lawless]

 

[bfoosh006]

I completely understand a bad day where groups just don’t group for some reason. Feel free to clutter this thread I seriously have zero issue with it. If it’s good info I believe it’s important to share data. Don’t forget; your the whole reason I’m jumping head first down this true and glue Rabbit Hole!!!!!!!!

As I said... I am eagerly looking forward to your results.

If anyone would like to see my results.. message me, I will send my results.

Otherwise, I am gonna wait to post a link.

I want to see if my results were a fluke... Lol ( turned out to be a great beneficial one though, and so far every barrel / caliber has responded very well )

I have just lapped more uppers in a few AR pistols, with PSA uppers w/ FN CHF CL barrels ... no glue yet.

I figured if those two FN factory barrels improve... then anything can.

I mean... we all know CL barrels aren't known for accuracy... right ? ..... chuckle.

One in 300BK 8.5" ... one in 5.56 10.5" ... I want to see if the glue is "needed"

 

[Sogan]

In for results. My BCM upper was so tight I couldn’t even get my lapping tool into the upper, let alone be able to turn it if I couldn’t get it seated. I had to heat the upper quite a bit to get the barrel in.

 

[Juggerxxx]

In for results. My BCM upper was so tight I couldn’t even get my lapping tool into the upper, let alone be able to turn it if I couldn’t get it seated. I had to heat the upper quite a bit to get the barrel in.

I was surprised at how tight a fit the PSA upper and barrel acually were. I almost had to heat it up to remove the barrel.
My lapping tool would also not fit in the business end of the upper. I had to take it into work, chuck it up in the lathe and polish it down until it would fit in the upper.

 

[Juggerxxx]

As I said... I am eagerly looking forward to your results.

If anyone would like to see my results.. message me, I will send my results.

Otherwise, I am gonna wait to post a link.

I want to see if my results were a fluke... Lol ( turned out to be a great beneficial one though, and so far every barrel / caliber has responded very well )

I have just lapped more uppers in a few AR pistols, with PSA uppers w/ FN CHF CL barrels ... no glue yet.

I figured if those two FN factory barrels improve... then anything can.

I mean... we all know CL barrels aren't known for accuracy... right ? ..... chuckle.

One in 300BK 8.5" ... one in 5.56 10.5" ... I want to see if the glue is "needed"

Here are some pictures of the surface a few steps along the way through lapping.

 

[Juggerxxx]

I trued my PSA 6.5C upper and shimmed the barrel in tight with stainless shim stock. Still have not shot it, my business is crazy busy since March but as soon as possible I will get it zeroed. Ordered an Ares BTR 4.5-27 on sale to switch places with the Argos and haven’t even fired it LOL.

@bfoosh006 is a wealth of information on these.


View attachment 7081049

View attachment 7081048

I trued my PSA 6.5C upper and shimmed the barrel in tight with stainless shim stock. Still have not shot it, my business is crazy busy since March but as soon as possible I will get it zeroed. Ordered an Ares BTR 4.5-27 on sale to switch places with the Argos and haven’t even fired it LOL.

@bfoosh006 is a wealth of information on these.

View attachment 7081049

View attachment 7081048

Holy crap you still haven’t shot that thing yet. I was about to give up on your PSA thread. I do recall you also had a death in the family as well. Please update us and the thread when you do finally shoot it.

 

[Yondering]

Thank you for the suggestion Sir! I will pick some of the 680 up instead. Have you even done a comparison before and after and if so did it ever make groups, consistency or POA worse?

Yeah, I've compared before and after on a few different AR rifles, but haven't documented the results. It's important to understand that this "true and glue" thing as you guys are calling it now is really two different things, with two different results.

Lapping the receiver is done to achieve full bolt lug engagement, and is really for bolt durability, not accuracy. I've seen a couple ARs go from only bearing on some of the lugs to full contact with lapping. That's a good thing for bolt life, but may never show up on target unless things were really bad or you're comparing the difference in benchrest-quality groups. This is the AR version of blueprinting a bolt action, or at least lapping the bolt lugs.

"Gluing" the barrel in the upper is really bedding, and it can definitely improve groups and make the rifle more consistent with a wider range of loads in my experience. The only thing better than bedding the barrel to the upper is using a thermo-fit (or press fit) upper like BCM with a quality barrel; with a shrink fit like that you don't need adhesive.

 

[Yondering]

In for results. My BCM upper was so tight I couldn’t even get my lapping tool into the upper, let alone be able to turn it if I couldn’t get it seated. I had to heat the upper quite a bit to get the barrel in.

You don't need to lap a BCM upper with a tight fit like that; the tight shrink-fit bore aligns the barrel extension to the receiver. In looser receiver fits, lapping is more helpful because the receiver face aligns the barrel extension.

 

[Yondering]

Here are some pictures of the surface a few steps along the way through lapping.

Looks like that definitely needed some lapping! Take a look at your bolt lug contact (easiest to see if you haven't cleaned the bolt, or use a small mirror and look inside the barrel extension at the front side of the lugs). You'll probably see partial contact on some lugs, and should expect full contact on all of them after that lapping job.

 

[Juggerxxx]

Yeah, I've compared before and after on a few different AR rifles, but haven't documented the results. It's important to understand that this "true and glue" thing as you guys are calling it now is really two different things, with two different results.

Lapping the receiver is done to achieve full bolt lug engagement, and is really for bolt durability, not accuracy. I've seen a couple ARs go from only bearing on some of the lugs to full contact with lapping. That's a good thing for bolt life, but may never show up on target unless things were really bad or you're comparing the difference in benchrest-quality groups. This is the AR version of blueprinting a bolt action, or at least lapping the bolt lugs.

"Gluing" the barrel in the upper is really bedding, and it can definitely improve groups and make the rifle more consistent with a wider range of loads in my experience. The only thing better than bedding the barrel to the upper is using a thermo-fit (or press fit) upper like BCM with a quality barrel; with a shrink fit like that you don't need adhesive.

Is this the type of damage one might see if there wasn’t full bolt engagement; in your opinion? That is actually my photo from this same rifle.

I had also formulated in my head that lapping the face would remove any high points that could also cause the barrel to rock, tilt or move when the upper and barrel heated up?

 

[bfoosh006]

Yeah, I've compared before and after on a few different AR rifles, but haven't documented the results. It's important to understand that this "true and glue" thing as you guys are calling it now is really two different things, with two different results.

Lapping the receiver is done to achieve full bolt lug engagement, and is really for bolt durability, not accuracy. I've seen a couple ARs go from only bearing on some of the lugs to full contact with lapping. That's a good thing for bolt life, but may never show up on target unless things were really bad or you're comparing the difference in benchrest-quality groups. This is the AR version of blueprinting a bolt action, or at least lapping the bolt lugs.

"Gluing" the barrel in the upper is really bedding, and it can definitely improve groups and make the rifle more consistent with a wider range of loads in my experience. The only thing better than bedding the barrel to the upper is using a thermo-fit (or press fit) upper like BCM with a quality barrel; with a shrink fit like that you don't need adhesive.

We are actually talking about lapping the upper receiver face , where the barrels receiver extensions "collar" makes contact with the upper.

Or at least I am !! Lol

 

[bigjake83]

We are actually talking about lapping the upper receiver face , where the barrels receiver extensions "collar" makes contact with the upper.

Or at least I am !! Lol

Yes he is to, basically when you true the receiver face you are just making sure that everything is concentric to the bore line, and the loctite is used to make sure it stays put.

 

[Lawless]

Holy crap you still haven’t shot that thing yet. I was about to give up on your PSA thread. I do recall you also had a death in the family as well. Please update us and the thread when you do finally shoot it.

I know bro, my business is literally insane right now.

 

[Yondering]

We are actually talking about lapping the upper receiver face , where the barrels receiver extensions "collar" makes contact with the upper.

Or at least I am !! Lol

Yes, that's exactly what I'm talking about. That surface gets lapped perpendicular to the receiver bore, so that the bolt lugs in the barrel extension are held perpendicular to the bore rather than at a slight angle. This ensures full bolt lug engagement; it is not an accuracy improvement but a durability improvement. Unfortunately a number of people here insist on asking about accuracy improvements from lapping; that's not what it's for.

The bonding, on the other hand, is done for accuracy, and you are likely to see some improvement as I described above.

 

[bigjake83]

Yes, that's exactly what I'm talking about. That surface gets lapped perpendicular to the receiver bore, so that the bolt lugs in the barrel extension are held perpendicular to the bore rather than at a slight angle. This ensures full bolt lug engagement; it is not an accuracy improvement but a durability improvement. Unfortunately a number of people here insist on asking about accuracy improvements from lapping; that's not what it's for.

You are completely contradicting your own theory!

It's the same as blue printing (Truing) a Rem 700 receiver, by making everything concentric to the center of the bore you are in fact aiding in the platforms accuracy by giving true repeatability in a sequence of mechanical movements.

AR rifles are machines and like all other machines, operate correctly when all moving parts are in unison. It's the same as balancing your tires on a vehicle, if your tires are not balanced correctly the harmonics and vibrations will affect and put strain on other parts, Hence affecting the platforms "durability" and optimized performance which affects its "accuracy".

They go hand-in-hand together, optimize mechanical performance is durability and accuracy.

Surface gets lapped perpendicular to the receiver bore, so that the bolt lugs in the barrel extension are held perpendicular to the bore rather than at a slight angle. This ensures full bolt lug engagement; it is not an accuracy improvement

This was painful to even read, I gonna see if I can get Glen Seekins to touch on this topic.

 

[SupressYourself]

Why are people so obsessed with being "right"?
How about we just say that lapping helps with full bolt engagement, and may also have some accuracy benefits?

 

[bfoosh006]

Yes he is to, basically when you true the receiver face you are just making sure that everything is concentric to the bore line, and the loctite is used to make sure it stays put.

This part was what I was referring to...

"Lapping the receiver is done to achieve full bolt lug engagement, and is really for bolt durability, not accuracy. I've seen a couple ARs go from only bearing on some of the lugs to full contact with lapping. That's a good thing for bolt life, but may never show up on target unless things were really bad or you're comparing the difference in benchrest-quality groups. This is the AR version of blueprinting a bolt action, or at least lapping the bolt lugs. "

And , yes lapping should help even out the lugs engagement as well. ( Although there have been 100,000's that have been fine without it... Lol )

When you lap the upper face , seeing the visual improvements there... makes it easy to forget the bolt lug engagement potential improvement.

 

[bfoosh006]

Yes, that's exactly what I'm talking about. That surface gets lapped perpendicular to the receiver bore, so that the bolt lugs in the barrel extension are held perpendicular to the bore rather than at a slight angle. This ensures full bolt lug engagement; it is not an accuracy improvement but a durability improvement. Unfortunately a number of people here insist on asking about accuracy improvements from lapping; that's not what it's for.

The bonding, on the other hand, is done for accuracy, and you are likely to see some improvement as I described above.

FWIW... I am going to test this very subject ( the truing vs. Truing and "Glueing" ) on a 10.5" 5.56, and a 8.5" 300BK... I also have a Kreiger waiting to be installed in 22" 6.5CM... I "might" do the same testing.

I tend to think, even having fuller / truer contact, from the RE barrels collar to upper receiver face should at the very least help with more consistent groups.. ( less fliers ? )

 

[garandman]

FWIW.... I just had my barrel come loose right in the middle of testing loads. After months of testing dozens of different boolits, powders, charges, seating depths, etc.. .JUUUUUSSSSTTT when I thot I'd found my load.... my barrel came loose. Ugh.



Plan accordingly.

 

[bigjake83]

Why are people so obsessed with being "right"?
How about we just say that lapping helps with full bolt engagement, and may also have some accuracy benefits?

It's not about obsessive compulsion to be correct, it about putting out the correct and most accurate information for all others to learn.

doesn't do anybody any good if they're only reading half the story.

 

[Spblademaker]

I trued my PSA 6.5C upper and shimmed the barrel in tight with stainless shim stock. Still have not shot it, my business is crazy busy since March but as soon as possible I will get it zeroed. Ordered an Ares BTR 4.5-27 on sale to switch places with the Argos and haven’t even fired it LOL.

@bfoosh006 is a wealth of information on these.

View attachment 7081049

View attachment 7081048

You’re gunna like the Ares Grabbed one earlier this year.

 

[Greg Langelius *]

Right now, I have a new pair of AR Stoner Uppers in 6.5 Grendel.

One is factory made with a 20" Heavy Fluted SS barrel, the other is a self-assembled 24" with the same source barrel and all AR Stoner parts.

When I assembled the 24", I trued and glued with Loc-tite 271 Red. Please note the Loc-Tite selector guide; which is also accessible through this link.

It is my intention to sight-in and load test the 24", and then sight-in and do the same to the 20". I intend to then disassemble the 20" (if it's possible), and true/glue the Upper/Barrel Extension same as the 24", as a comparison to see if the true/glue process has significant advantage for me.

The two uppers have been equipped with identical bipods, optics, and mounts, to cut down on the variables. They will be fired atop the same Stag Model 6 Super Varminter with the Stag 2-stage trigger.

The initial rounds will be Wolf Military Classic 100gr Bimetallic, which will probably hone the bore quicker than conventional ammo. After that, the rest of the 500rd case of the Wolf will be relegated to the back of the ammo storage for "last ditch" usage only.

After some extensive Internet research, I have concluded that the AR Stoner barrels are most likely sourced from Liberty, which is the button-rifled in-house brand from Satern. Not Gospel, but I'm kinda convinced.

Greg

PS, I haven't tried this, but it looks like it might have a place in this discussion.

 

[bigjake83]

Loctite 680 is probably the best for this application but the 271 is usually what most people have on hand and I haven't been able to see a difference, they both work.

One way to tell which one performs better is when you remove your Barrel after its been shot out, you should be able to see inside the upper receivers Barrel extension channel a perfect sleeve/shim that has been created by the loctite.

I've pulled quite a few barrels that I used 271 with over the years and the loctite sleeve is still perfect, no cracks or flakes. I can't vouch for the 680 yet because all of my uppers that I've used that with still have perfect shooting barrels.

 

[Juggerxxx]

Loctite 680 is probably the best for this application but the 271 is usually what most people have on hand and I haven't been able to see a difference, they both work.

One way to tell which one performs better is when you remove your Barrel after its been shot out, you should be able to see inside the upper receivers Barrel extension channel a perfect sleeve/shim that has been created by the loctite.

I've pulled quite a few barrels that I used 271 with over the years and the loctite sleeve is still perfect, no cracks or flakes. I can't vouch for the 680 yet because all of my uppers that I've used that with still have perfect shooting barrels.

Sounds like you can answer a question I have. How do you or what is best way to pull a barrel after using some form of Loctite? Somewhat short sighted on my part but I just thought about this question after committing to glueing my barrel?

 

[bigjake83]

Sounds like you can answer a question I have. How do you or what is best way to pull a barrel after using some form of Loctite? Somewhat short sighted on my part but I just thought about this question after committing to glueing my barrel?

It's not really "Gluing" the loctite generally only adheres to the receiver. It's not that bad to remove a barrel if loctite as been used, it's removing a barrel that's been Thermo fitted that's a pain in the ass. I have a hard plastic rod that is the same diameter as the barrel, put some heat on the front and just tap it out.

 

[Juggerxxx]

It's not really "Gluing" the loctite generally only adheres to the receiver. It's not that bad to remove a barrel if loctite as been used, it's removing a barrel that's been Thermo fitted that's a pain in the ass. I have a hard plastic rod that is the same diameter as the barrel, put some heat on the front and just tap it out.

That’s what I had hoped to hear. The loctite just acts as a filler to fill in any of the gaps between the extension and the upper.

 

[Yondering]

You are completely contradicting your own theory!

Slow down and read things a little more carefully. I didn't contradict anything, or present any theory. See my earlier post in this thread where I said this:

That's a good thing for bolt life, but may never show up on target unless things were really bad or you're comparing the difference in benchrest-quality groups. This is the AR version of blueprinting a bolt action, or at least lapping the bolt lugs.

But no, durability and accuracy do not "go hand in hand". They really have nothing to do with each other and any correlation is just coincidence in certain situations.

Were you drinking when you posted that, or what? You switch moods like crazy on this forum, going from reasonable discussion to full on dickhead with no provocation. Why?

 

[3-0-hate]

I just "T&G'd" a couple of upper receivers. Im very interested to see how it goes. I may even T&G my white oak A2 service rifle if I get good results on the PRS trainer I built.

Does anyone have any before and after results yet?

 

[bigjake83]

I use a 1” dowel rod to remove the barrel. And sometimes when i can’t find that, a 1/2” drive socket and extension works too. 18mm in my kit if I remember right.

I used to use a socket and an extra-long extension when I first started doing this stuff but the metal-on-metal contact just made me to leary of causing damage accidentally.

 

[Juggerxxx]

I received the 680 loctite today and found the time to glue the extension into the upper. I applied the loctite to both the extension and the upper for good measure and cleaned off the excess. This whole process has been super easy so even if it doesn’t make a difference I am only out the money used in tools and loctite. I just hope it doesn’t make things worse.
I hope to find time this weekend between birthday parties and graduations to test and see the results.

 

[bfoosh006]

Loctite 680 is a good "version" as well... it is for larger gaps... 0.015 in. And has a higher sheer strength 4000psi

609 is for tighter gaps...0.006 in. ... 2300psi

 

[FishinGuns]

When you go to replace a barrel, how do you remove the loctite from the upper receiver? Heat it up and scrape with plastic? I’ve loctited my barrels, but I’m nowhere near shooting them out yet.

Thanks in advance!

 

[blacknwhite11]

........just waiting for real world before and after results...........

 

[Juggerxxx]

When you go to replace a barrel, how do you remove the loctite from the upper receiver? Heat it up and scrape with plastic? I’ve loctited my barrels, but I’m nowhere near shooting them out yet.

Thanks in advance!

I had asked the same question above. From what I understand the loctite doesn’t really adhere the two surfaces together rather it fills in any of the gaps between the two surfaces. Tapping the barrel out may still be necessary with a wooden dowel.

 

[FishinGuns]

Works for me!

 

[garandman]

When you go to replace a barrel, how do you remove the loctite from the upper receiver? Heat it up and scrape with plastic? I’ve loctited my barrels, but I’m nowhere near shooting them out yet.

Thanks in advance!

In part its the difference btwn red and blue loctite. "Red" locktite is semi-permanent.

Blue loctite just helps minimise threaded items from unthreading. With a litle extra torque, blue loctited parts can be disassembled.

See here: http://henkeladhesivesna.com/blog/the-difference-between-red-blue-green-and-purple-threadlockers/

 

[FishinGuns]

It's not really "Gluing" the loctite generally only adheres to the receiver. It's not that bad to remove a barrel if loctite as been used, it's removing a barrel that's been Thermo fitted that's a pain in the ass. I have a hard plastic rod that is the same diameter as the barrel, put some heat on the front and just tap it out.

This is what I’m getting at, actually. I fully understand the loctite will stick to the the upper receiver. When I eventually tap out my old barrels, does the loctite that’s adhered to the inside of the upper receiver peel out with some persuasion?

 

[bigjake83]

This is what I’m getting at, actually. I fully understand the loctite will stick to the the upper receiver. When I eventually tap out my old barrels, does the loctite that’s adhered to the inside of the upper receiver peel out with some persuasion?

Yep, or sometimes if there's no cracks or chips in it just heated up the receiver a little a bit and slide in your new Barrel. But for me I would always recommend removing the old stuff and applying new, just make a scraping tool out of something that's hard plastic and it comes off relatively easy.

 

[FishinGuns]

That’s exactly what I hoping to hear! Thank you?

 

[gopherslayer]

Right now, I have a new pair of AR Stoner Uppers in 6.5 Grendel.

One is factory made with a 20" Heavy Fluted SS barrel, the other is a self-assembled 24" with the same source barrel and all AR Stoner parts.

When I assembled the 24", I trued and glued with Loc-tite 271 Red. Please note the Loc-Tite selector guide; which is also accessible through this link.

It is my intention to sight-in and load test the 24", and then sight-in and do the same to the 20". I intend to then disassemble the 20" (if it's possible), and true/glue the Upper/Barrel Extension same as the 24", as a comparison to see if the true/glue process has significant advantage for me.

The two uppers have been equipped with identical bipods, optics, and mounts, to cut down on the variables. They will be fired atop the same Stag Model 6 Super Varminter with the Stag 2-stage trigger.

The initial rounds will be Wolf Military Classic 100gr Bimetallic, which will probably hone the bore quicker than conventional ammo. After that, the rest of the 500rd case of the Wolf will be relegated to the back of the ammo storage for "last ditch" usage only.

After some extensive Internet research, I have concluded that the AR Stoner barrels are most likely sourced from Liberty, which is the button-rifled in-house brand from Satern. Not Gospel, but I'm kinda convinced.

Greg

PS, I haven't tried this, but it looks like it might have a place in this discussion.

They used to be Satern/Liberty. The new ones are supposedly Bear Creek unfortunately. I have an older one that’s a Liberty barrel and it’s superb. My new 6.5G barrel isn’t the best so I ordered a 6.5GARP.

 

[Juggerxxx]

Hit the range today after trueing and glueing. Not really sure what to think about the results other than I don’t believe this made a big difference either way for me and my rifle.
The 147gr groups actually got slightly larger as in +0.319”.
The 140gr groups got smaller by -0.283”.
The 147gr and 140gr group size average before was 0.953”
The 147gr and 140gr group size average after was 0.971”
To me this is just spitting hairs and I can’t explain why the 147gr groups got worse and the 140gr groups got better.
I know there is an argument weather lapping the upper changes the distance to the lands but that had crossed my mind? Maybe it was just one of those days? I have noticed that some loads shoot better some days then others but besides humidity the temperature was about the same?
Anyway; interpret my results as you wish and I am open to any and all ideas or conclusions.

 

[bigjake83]

Hit the range today after trueing and glueing. Not really sure what to think about the results other than I don’t believe this made a big difference either way for me and my rifle.
The 147gr groups actually got slightly larger as in +0.319”.
The 140gr groups got smaller by -0.283”.
The 147gr and 140gr group size average before was 0.953”
The 147gr and 140gr group size average after was 0.971”
To me this is just spitting hairs and I can’t explain why the 147gr groups got worse and the 140gr groups got better.
I know there is an argument weather lapping the upper changes the distance to the lands but that had crossed my mind? Maybe it was just one of those days? I have noticed that some loads shoot better some days then others but besides humidity the temperature was about the same?
Anyway; interpret my results as you wish and I am open to any and all ideas or conclusions. View attachment 7084987

Regardless of your turnout I still applied you for your shooting, you are well and truly doing better than most people I see on here. Shooting a large frame AR proficiently is no easy task and maybe this range trip hasn't proven anything concrete to the argument but judging by your groups and if you decide to stick with this platform I believe you are capable of being a 1/2 MOA Shooter.

This is just my opinion but by reading your groups it looks like the reason behind your point of impact shift would be due from changing your grip or canting your rifle.

 

[TonyTheTiger]

I know there is an argument weather lapping the upper changes the distance to the lands but that had crossed my mind?

Nope, not a thing.

 

[Mike_in_FL]

Hit the range today after trueing and glueing. Not really sure what to think about the results other than I don’t believe this made a big difference either way for me and my rifle.
The 147gr groups actually got slightly larger as in +0.319”.
The 140gr groups got smaller by -0.283”.
The 147gr and 140gr group size average before was 0.953”
The 147gr and 140gr group size average after was 0.971”
To me this is just spitting hairs and I can’t explain why the 147gr groups got worse and the 140gr groups got better.
I know there is an argument weather lapping the upper changes the distance to the lands but that had crossed my mind? Maybe it was just one of those days? I have noticed that some loads shoot better some days then others but besides humidity the temperature was about the same?
Anyway; interpret my results as you wish and I am open to any and all ideas or conclusions. View attachment 7084987

Realistically speaking you don't have much of a sample size. There's nothing wrong with your groups, looks like the 140s tightened up a hair today with a couple that might be on you.

As far as the 147s go, did you start with those cold? A cold shooter shoots differently. I would be very happy with those results.

 

[bigjake83]

Nope, not a thing.

And I forgot to touch on that, upper receiver truing, can't affect that because headspacing is controlled by the bolt and the barrel extension. The upper receiver is merely a guiding system holding these two objects in line with one another.