User Panel
User Panel
User Panel
USA
|
Posted: 6/24/2016 12:33:35 AM EDT
Does anyone have any personal experience having the upper receiver fave squared? Waste of time/money?
|
|
|
|
Posted: 6/24/2016 8:23:53 AM EDT
[#1]
for an ar?
|
|
|
|
FL, USA
|
Posted: 6/24/2016 8:27:30 AM EDT
[#2]
Take a read through this, can't remember if the squaring part was in it or not but some useful stuff... I saved it for the part about shimming...might do that on one of my rifles...
http://www.ar15.com/forums/t_16_4/42_Hellbenders_guides_to_Ultimate_AR15_and_or_AR10.html |
|
|
USA
|
Posted: 6/24/2016 9:13:03 AM EDT
[#3]
Quote HistoryOriginally Posted By mayorbilk:
for an ar? Correct |
|
|
|
Posted: 6/24/2016 12:16:43 PM EDT
[#4]
I have one of THESE that I have used on my precision rifles.
I have no idea how much difference it makes because I didn't do any before/after comparisons. |
|
|
|
|
Posted: 6/25/2016 12:46:35 PM EDT
[#5]
Squaring the face to what? The threads? The bore of the upper? If you don't square all 3 to each other you're basically wasting your time.
|
|
|
|
|
Posted: 7/16/2016 7:44:02 PM EDT
[Last Edit: MS556]
[#6]
Quote HistoryOriginally Posted By mitsuman47:
Squaring the face to what? The threads? The bore of the upper? If you don't square all 3 to each other you're basically wasting your time. No waste of time to have a precise flat surface to torque the barrel extension to. I understand what you are saying about the assumptions being made, but It seems worthwhile that the surface be absolutely flat and on the same plane as the bore of the upper that the mandrel slides within during the process. 
I guess it didn't hurt. 
|
|
|
|
|
Posted: 7/16/2016 7:51:23 PM EDT
[#7]
I've done it to several. Some needed it, some didn't. No way to tell until you do it and observe the wear pattern on the face.
|
|
|
|
SC, USA
|
Posted: 7/18/2016 7:16:10 AM EDT
[#8]
I had a 6.8 upper that required almost all the windage my 1-4 PST had just to get on paper at 100 yds. I thought it came with a bent barrel, but had the same problem when I swapped it with a new one. When I lapped the receiver, it was obvious that the face was off by a lot--one side was a few thousandths higher than the opposite. After lapping, the 100 yd zero was within a few clicks of the mechanical zero of the scope.
Lapping only takes a few minutes, and after chasing the problems with that 6.8, I lap every new receiver now. Better to take care of any potential problems during the initial build than waste the ammo and effort later. |
|
|
IA, USA
|
Posted: 7/18/2016 8:35:14 PM EDT
[#9]
I did it on my Grendel. I'm not sure if it did anything, but I can't see why it would hurt. Go for it.
|
|
|
MS, USA
|
Posted: 6/28/2017 1:57:08 AM EDT
[#10]
I have lapped about 6 or 7 uppers. Mostly Anderson which were all good. 2 aero precision were also good.
I only had 1 PSA upper that had a high spot from a factory 6.8 upper. it WAS causing trouble with that upper as in 6 moa groups. Afterwards, 2 moa. |
|
|
|
Posted: 6/28/2017 2:01:20 AM EDT
[#11]
It's beneficial.
Probably the best thing though is a press fit between the barrel and upper. |
|
|
|
|
Posted: 6/28/2017 3:35:52 PM EDT
[#12]
Quote HistoryOriginally Posted By mitsuman47:
Squaring the face to what? The threads? The bore of the upper? If you don't square all 3 to each other you're basically wasting your time. A lot of receivers need it. I've done before and after with a LW JP .223 Wylde barrel. I slapped it together first, it shot maybe 1.5-1.7" at 100yds with good ammo. Lapped the receiver face, bedded it, and it shrunk down to .25" groups, laser-like. Friend of mine let his daughter shoot it, and she was cutting tiny groups at 100yds like it was fun, no experience on rifles before really. I can usually predict where the shot dispersion will be from center with an unlapped receiver face if I check it, provided the crown is square. The face will be square to the carrier raceway with the lapping tool, since the fit is so close and I hold the receiver vertically when I do it. The lapping tool needs lubrication to turn inside the upper, it is pretty tight, and will not bias to gravity when held vertically. |
|
|
|
FL, USA
|
Posted: 6/28/2017 3:53:51 PM EDT
[#13]
I did it to mine, did not shoot it before and I am happy with the results.
Good info about doing it vertically for my next build though. |
|
|
USA
|
Posted: 6/28/2017 4:24:45 PM EDT
[Last Edit: rpoL98]
[#14]
|
|
|
|
Posted: 6/28/2017 6:57:05 PM EDT
[Last Edit: borderpatrol]
[#15]
Firearms News had an article in the last issue that was effed up. The
"gunsmith" suggested using a file or sand paper on a flat surface. He said "be careful to keep it square". That article should have never been printed. He did also suggest buying Brownells excellent tool which is the only thing he should have suggested to begin with. If you own a metal lathe or have access to one you can face the upper square, making sure you only remove just enough material and nothing more. We're talking a few thousandth?'s. I have Brownells tool and use it on every build now. There's no reason not to. It only takes 5 minutes +/- and I think it helps. |
|
|
|
|
Posted: 6/29/2017 1:53:00 AM EDT
[#16]
Quote HistoryOriginally Posted By LRRPF52:
The face will be square to the carrier raceway with the lapping tool, since the fit is so close and I hold the receiver vertically when I do it. The lapping tool needs lubrication to turn inside the upper, it is pretty tight, and will not bias to gravity when held vertically. I liberally lube the inside of the receiver and the "pilot" with a heavy weight oil. |
|
|
|
|
Posted: 6/29/2017 3:24:13 AM EDT
[#17]
what is this brownells excellent tool? link is broken
|
|
|
|
|
Posted: 6/29/2017 11:29:37 PM EDT
[Last Edit: StellarTyGuy]
[#18]
It's unavailable at Brownells right now , but this is in stock at Midway
|
|
|
|
|
Posted: 7/3/2017 8:32:31 PM EDT
[#19]
I'm doing a build with the primary focus being accuracy. I sent two upper receivers out to Paladin to have the front end squared. I didn't want it to be lingering in the back of my mind as something that could negatively affect accuracy. A machine shop with a lathe is the only way I see to do it.I dont trust the lapping tools from any manufacturer as they are made to fit every receiver, therefore they have to run on the small end. The two receivers I sent out were on opposite ends of the spectrum. One barely needed anything removed, the other...quite a bit. But barrels now sit in either and don't move. So, at least to me, there is merit in having it done.
|
|
|
|
GA, USA
|
Posted: 7/4/2017 9:28:48 AM EDT
[#20]
This is the one I just used. Worked well.
http://pacifictoolandgauge.com/ar-tools/1139-ar-15-upper-receiver-lapping-tool.html |
|
|
|
Posted: 7/4/2017 3:00:58 PM EDT
[#21]
Quote HistoryOriginally Posted By LRRPF52:
Nope. You can see the effects on lug engagement alone, which is enough of a reason to do it even if you don't care about accuracy. A lot of receivers need it. I've done before and after with a LW JP .223 Wylde barrel. I slapped it together first, it shot maybe 1.5-1.7" at 100yds with good ammo. Lapped the receiver face, bedded it, and it shrunk down to .25" groups, laser-like. Friend of mine let his daughter shoot it, and she was cutting tiny groups at 100yds like it was fun, no experience on rifles before really. I can usually predict where the shot dispersion will be from center with an unlapped receiver face if I check it, provided the crown is square. The face will be square to the carrier raceway with the lapping tool, since the fit is so close and I hold the receiver vertically when I do it. The lapping tool needs lubrication to turn inside the upper, it is pretty tight, and will not bias to gravity when held vertically. |
|
|
|
MD, USA
|
Posted: 7/5/2017 12:06:02 PM EDT
[#22]
Using the Brownells tool I've squared the front face of about 12 receivers, and IMHO quality uppers (Colt, BCM, FN, Mega) do not need to be squared, but cheap ones (PSA $29 special) do.
|
|
|
|
Posted: 7/5/2017 9:27:39 PM EDT
[#23]
Quote HistoryOriginally Posted By 2JokersWild:
You mean that a lapping tool alone counted for a better than a 1" improvement in your group sizes? I've no doubt the lapping tool can help, but that seems like an incredibly large difference for such an overlooked step in a rifle build. Your statement there would put lapping the receiver face as potentially being more important than a upgraded trigger or even an upgraded barrel....... Quote HistoryOriginally Posted By 2JokersWild:
Originally Posted By LRRPF52:
Nope. You can see the effects on lug engagement alone, which is enough of a reason to do it even if you don't care about accuracy. A lot of receivers need it. I've done before and after with a LW JP .223 Wylde barrel. I slapped it together first, it shot maybe 1.5-1.7" at 100yds with good ammo. Lapped the receiver face, bedded it, and it shrunk down to .25" groups, laser-like. Friend of mine let his daughter shoot it, and she was cutting tiny groups at 100yds like it was fun, no experience on rifles before really. I can usually predict where the shot dispersion will be from center with an unlapped receiver face if I check it, provided the crown is square. The face will be square to the carrier raceway with the lapping tool, since the fit is so close and I hold the receiver vertically when I do it. The lapping tool needs lubrication to turn inside the upper, it is pretty tight, and will not bias to gravity when held vertically. I might have used the AR10 hammer spring with it too, can't remember. There's another recent thread where a guy did it and shrunk his groups substantially. I was sold when I saw the before/after with the JP 18" barrel. That barrel had been abused with cases of M855 through it as well. A friend gave it to me saying he was just going to throw it in the trash if I didn't want it. Had the ventilator fins, adjustable gas block, Cooley brake, and gas tube. Thing shoots lights-out. |
|
|
|
AZ, USA
|
Posted: 7/7/2017 5:40:08 PM EDT
[#24]
I only have about 8ish AR variants. 6 ive built on my own. my first "precision" built was my 308 AR. Granted i used very high quality parts so thats prob why im getting such good results, but it was also the first receiver i had lapped (barely even needed it, but did have a pinch of a high spot). did it make a accuracy difference, idk. didnt do a before/after. but its a great shoot. A few builds between and i never lapped them. When i did my 5.56 precision rifle though, i did lap it. again idk if it makes a difference, but figured i might as well.
|
|
|
Win a FREE Membership!
Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!
You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.
AR15.COM is the world's largest firearm community and is a gathering place for firearm enthusiasts of all types.
From hunters and military members, to competition shooters and general firearm enthusiasts, we welcome anyone who values and respects the way of the firearm.
Subscribe to our monthly Newsletter to receive firearm news, product discounts from your favorite Industry Partners, and more.
Copyright © 1996-2024 AR15.COM LLC. All Rights Reserved.
Any use of this content without express written consent is prohibited.
AR15.Com reserves the right to overwrite or replace any affiliate, commercial, or monetizable links, posted by users, with our own.
