View Full Version : Wasted 100 rounds chasing my zero.. somebitch...
colorider
07-10-2013, 22:41
Have a factory assembled LMT carbine upper that I have had for a year or so. Put several rounds through it with open sights and a cheap red dot. Figured my accuracy issues were with the fact I was new to the AR platform and the open sights and low quality optic. Well, about 3 weeks ago my wallet puked up money and I bought a Browe BCO acog. The damn thing would not hold zero to save its life. 3 trips to the range and frustration and blaming myself.
Well today I decide to call Browe and ask the owner Brian about sending the optic to him to have them look at it and see what the heck is going on. He said send it in asap and he will have a new one out to me within 24 hours. He then tells me to check my barrel nut. Hummmm,,,,, Barrel nut? Never thought to think of that because I purchased a factory assembled high quality upper and barrel. Well I will be damned, the damn nut was finger tight. How I never noticed this when cleaning it or shooting it I will never know. Kinda pisses me off really. Not even close to torque specs. After removing the gas tube, I spun the nut off by hand. No way this could have happended over time because the way the tube holds the nut in place.
Damn. I can understand why you would expect better than that.
Great-Kazoo
07-10-2013, 23:10
LMT isn't the only mfg with hand tight bbl nuts.
LMT isn't the only mfg with hand tight bbl nuts.
Who else is doing that ? That's insane.
ChunkyMonkey
07-10-2013, 23:16
That's why I brought mine to Jim's garage. While you wait outside, he summons Chuck Norris to hand tight the barrel nut. I just wish mr Norris won't have to leave so quickly... Never had a chance to thank him.
Building your own is nice. You know how it all went together and that work was done right. Especially in today's market where they were pumping them out as fast as they could go.
colorider
07-11-2013, 00:01
The thing is, I got this upper assembly way before any of the panic started. About a year before any sort of crap was going on. I have to say that in a a way I am happy that my $1300 optic is probably not to blame. Have to hit the range tomorrow and make sure that it was the loose barrel. From wiggling it on my bench, it looked to be exactly the amount of wiggle that would cause the amount of zero change I was seeing. Mostly elevation changes. That sucker is torqued down to spec now.
Building your own is nice. You know how it all went together and that work was done right. Especially in today's market where they were pumping them out as fast as they could go.
I agree 100%
Sent from my Otterbox Defended Tactical iPhone using High Capacity "Clips".
The thing is, I got this upper assembly way before any of the panic started. About a year before any sort of crap was going on. I have to say that in a a way I am happy that my $1300 optic is probably not to blame. Have to hit the range tomorrow and make sure that it was the loose barrel. From wiggling it on my bench, it looked to be exactly the amount of wiggle that would cause the amount of zero change I was seeing. Mostly elevation changes. That sucker is torqued down to spec now.
Just goes to show you that any brand out there can have its bad apples
BPTactical
07-11-2013, 05:31
I have seen numerous factory rifles with loose barrelnuts from the factory. As a matter of fact yesterday a gent was absolutely incensed that I suggested we check it as part of an accuracy issue on his new Les Baer rifle that is a top shelf item.
Just because you paid big bucks for the rifle doesn't mean it wasn't assembled by a $8.00 per hour knucklehead.
Great-Kazoo
07-11-2013, 06:47
I have seen numerous factory rifles with loose barrelnuts from the factory. As a matter of fact yesterday a gent was absolutely incensed that I suggested we check it as part of an accuracy issue on his new Les Baer rifle that is a top shelf item.
Just because you paid big bucks for the rifle doesn't mean it wasn't assembled by a $8.00 per hour knucklehead.
From Mt Olympus himself.
How true, New and "Tier 1" doesn't mean it's perfect. A lot of folks would be surprised how common under-torqued bbl nuts are. Not saying they need to be cheater bar tightened to 85 ft lbs either.
Remember. Cardboard's Maintenance Free.............................................. ...........Till it rains.
Not a big fan of lmt I having seen one built in the last few years that would run steel case......
colorider
07-11-2013, 09:35
I am sure that many lmt do not shoot steel cased ammo. They have a tighter chamber then most and that causes the steel to stick and not cycle properly. Also the more popular steel cased ammo such as Tula and Wolf is underpowered causing the sticking to be worse in an lmt. I have talked to several well known and reputable gunsmiths in town and on this site about it. One comment was that you would not put coleman camp fuel in a ferrari, why would you run steel in an LMT. The other said that the chamber could be reamed to shoot steel, but why would you want to do that.
All I can say is that I have never had a cycling problem in my lmt using any brass ammo. And that is with a barrel that was extremely loose.
I am sure that many lmt do not shoot steel cased ammo. They have a tighter chamber then most and that causes the steel to stick and not cycle properly. Also the more popular steel cased ammo such as Tula and Wolf is underpowered causing the sticking to be worse in an lmt. I have talked to several well known and reputable gunsmiths in town and on this site about it. One comment was that you would not put coleman camp fuel in a ferrari, why would you run steel in an LMT. The other said that the chamber could be reamed to shoot steel, but why would you want to do that.
All I can say is that I have never had a cycling problem in my lmt using any brass ammo. And that is with a barrel that was extremely loose.
didn't want to turn this into another another steel vs brass thread
Bailey Guns
07-11-2013, 10:19
How true, New and "Tier 1" doesn't mean it's perfect. A lot of folks would be surprised how common under-torqued bbl nuts are. Not saying they need to be cheater bar tightened to 85 ft lbs either.
I don't know how they are now, but Bushmaster barrels at one time were put on so tight it was damn near impossible to remove them without damaging the receiver. And gas key screws almost always needed to be removed, degreased and staked on. For a while every BM rifle I got into the shop had a loose gas key.
BPTactical
07-11-2013, 11:08
I don't know how they are now, but Bushmaster barrels at one time were put on so tight it was damn near impossible to remove them without damaging the receiver. And gas key screws almost always needed to be removed, degreased and staked on. For a while every BM rifle I got into the shop had a loose gas key.
Yup, Bushy for a while did not seem to understand what "properly staked" meant when it came to gas key screws.
Of course you can have the other end of the spectrum too, you don't know what fun is until you try to take off a barrelnut that was red Loctited on by a local firm(that is no longer around) that claimed to be "experts" on the AR platform and also claimed to build top tier rifles.
Lots of Loctite as a matter of fact.
Bailey Guns
07-11-2013, 11:22
Well...if a little Loctite's good, a lot must be better!
[Beer]
colorider
07-11-2013, 11:26
Yup, Bushy for a while did not seem to understand what "properly staked" meant when it came to gas key screws.
Of course you can have the other end of the spectrum too, you don't know what fun is until you try to take off a barrelnut that was red Loctited on by a local firm(that is no longer around) that claimed to be "experts" on the AR platform and also claimed to build top tier rifles.
Lots of Loctite as a matter of fact.
Oh shit , you mean I wasn't supposed to use a generous amount of red ?!?!?!?
J/k. I used 3 plops of blue. And torqued to 80#. It ain't moving.
Not a big fan of lmt I having seen one built in the last few years that would run steel case......
My Knights won't eat steel. I wouldn't even try it. As previously mentioned....it wasn't built to.
On a side note....how did you like the Browe?
Oh shit , you mean I wasn't supposed to use a generous amount of red ?!?!?!?
J/k. I used 3 plops of blue. And torqued to 80#. It ain't moving.
I believe it's "up to" 80lbs
BPTactical
07-11-2013, 12:09
Oh shit , you mean I wasn't supposed to use a generous amount of red ?!?!?!?
J/k. I used 3 plops of blue. And torqued to 80#. It ain't moving.
Totally uneccessary and fail.
Molybdenum based anti seize or white lithium based grease are the only substances to be used on a receiver/barrelnut assembly. DO NOT USE GRAPHITE BASED ANTI SEIZE!
Torque to 40Ft/Lbs dry 3 times and back off the nut each time. This burnishes the threads allowing an accurate final torque reading. On final installation lightly lubricate the receiver threads with the above, torque to 40Ft/Lbs. Additional torque may be required to line up the barrelnut notches for the gas tube not to exceed 80Ft/Lbs.
Once the gas tube is in place the barrelnut is not going anyplace, the gas tube is a very effective locking device.
Eugene Stoner was just a smidge wiser than people give him credit for.
Note: the above torque values and procedures are for standard barrel nuts. Many manufacturers of aftermarket components have their own values and procedures. If in doubt or if you have questions, contact the manufacturer.
colorider
07-11-2013, 12:56
To be honest , my loctitte is old and watery. Prob not even doing anything. I had tried 4x to get the torque less then 80, but the tube would simply not line up. Nut threaded on nice.
BPTactical
07-11-2013, 13:14
To be honest , my loctitte is old and watery. Prob not even doing anything. I had tried 4x to get the torque less then 80, but the tube would simply not line up. Nut threaded on nice.
I have run into a few of those before and they can be aggravating. Usually a different barrel nut cures that issue. In worst case scenarios you can get a timing washer, similar to what one uses for a muzzle device. Also the anti seize really reduces the torque required to time them up.
colorider
07-11-2013, 14:10
Bert, a day without learning something is a day wasted. Now my day is not wasted.
As far as the Browe bco goes. Today is the 1st time using it with a barrel that is not flopping around.
The optic is simply amazing. The glass is clearer then the trijicon and the chevron a lot crisper. The auto adjust on the chevron brightness is awesome. It senses the lighting off the target, not your surroundings. One of my groups was 4 shots all almost touching at the bullseye just now at 50 yds. From a bench and I am totally new to this type of optic. At 75 yds my group was about 1.75 inches.
VERY happy with the optic.
pics or it didn't happen ;)
Glad you got 'er figured, dude.
I really love this thread. Although I respect his opinion on the matter, I firmly disagree with Travis Haley when it comes to battle rifles. He believes those of us who build our own are "hobbyists" and the guns we build are nothing more than "hobby guns" and not up to SAAMI specs. I would gladly take my AR into combat any day of the week, no problem at all. I've ran it just as hard as I did my M4, if not harder and it ran like a top. That being said, sorry to hear you had the issue with your rifle, but glad you were able to trouble shoot it and nail down the problem. [Beer]
sabot_round
07-11-2013, 18:25
I have a friend's factory built in an A2upper here that I took to swap out for a flat top upper. I have done this at least a dozen times. Here is the kicker!! When I removed the upper and proceeded to install the new one, I proceeded to torque the barrel nut, and at less than 30 foot pounds, the entire upper twisted with it and I was in shock!! I thought that I had broken the damn receiver and I [panic]. Upon further troubleshooting I come to find out that the barrel extension has come loose while I was trying to torque up the barrel nut. Now the barrel extension won't line up with the fixed front sight, offsetting the upper receiver to the 1130 position instead of 1200 o'clock. I have tried everything available in my toolbox to get this thing torqued, but the reality is that I've misplaced the specs for the barrel extension, and this is the first time that I had to install a barrel extension. I've been considering taking this thing to a gunsmith but any suggestions will be greatly appreciated!!
BPTactical
07-11-2013, 18:33
Throw the entire upper assembly in the mail to me.
I really love this thread. Although I respect his opinion on the matter, I firmly disagree with Travis Haley when it comes to battle rifles. He believes those of us who build our own are "hobbyists" and the guns we build are nothing more than "hobby guns" and not up to SAAMI specs. I would gladly take my AR into combat any day of the week, no problem at all. I've ran it just as hard as I did my M4, if not harder and it ran like a top. That being said, sorry to hear you had the issue with your rifle, but glad you were able to trouble shoot it and nail down the problem. [Beer]
I'm guessing he said that because of the trend to build the cheapest ar possible I remember seeing thread after thread on arfcom about 450$ ars I also remember reading the pat Rodgers aars where these "Frankenguns" would seize up and delay classes
I personally think a homebuilt rifle with QUALITY parts will outshoot pretty much any off the shelf factory rifle out there as long as you take the time to put it together properly(or send it to Bert)
I would personally put my hello kitty rifle against anything out there (although with well over 10k through it I'm sure it would lose a beauty contest :)
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