View Full Version : A lesson on QC, due diligence, and testing before modifying.
Eurodriver
03-15-19, 18:36
Here is the rifle in question. Lower bought in 2009 with a brand new unfired 10.5" upper. I have neither disassembled the lower, nor the upper (I did cut off the delta ring assembly and handguard cap but I didn't remove the FSP or the barrel) A little bit of digging will tell you who made the upper, but I will keep it on the DL IAW site rules.
https://i.imgur.com/NfecO9s.jpg
Everything on the rifle has been vetted - FH, optic, BCG, CH, lower, etc except the upper.
I began zeroing it at 100y with the iron sights and immediately noticed the rear sight was all the way to the left for a good zero. This was a yellow flag, but it was shooting nicely so I drove on. I got about 1.5" at 100 yards with 64gr Gold Dots for my confirmation fire - right where I was aiming. I was happy.
I turned on the T2 and started to zero that. The first 10 rounds (about 25 total so far) went ok. I was shooting high right with Wolf Gold. Adjusted the T2 down and left.
That's when the fun started. My groups were then higher and righter. "There's no ****ing way I adjusted that incorrectly, but let's play the game" so I adjusted back twice the amount down and right (to compensate or any amount I might have done wrong)
This was the following target. I think it came out to be about an 18" extreme spread at 100 yards from a sandbag rest.
https://i.imgur.com/KaFs7WI.jpg?1
This was the next target with Speer Gold Dots. The highest 3 rounds were done unsuppressed which caused a POI shift upward, but the rest were suppressed. That's about 7 MOA at 100 yards with quality ammo.
https://i.imgur.com/NsRzeP3.jpg
It also had a failure to fire unsuppressed as the bolt jammed the new cartridge in the neck as it was attempting to feed. For a little perspective, I have not had a failure to fire of any kind in any AR15/M16 I have shot since 2007 when I was a young Lance Coolie in Iraq buying into the "Lube attracts dirt" mantra preached by more senior (and retarded) SNCOs.
Red flag.
At that point I went home. $10 is too much money to spend on 7 MOA groups. I checked the flash hider and the optic at the range. Both were fine.
When I got home I did a more thorough inspection and found this:
https://i.imgur.com/cNo2U3Y.mp4
The barrel nut shot loose on a brand new upper. (It took me a second to realize the nut itself is loose, and if it weren't for the anti rotation tabs/gas tube the hand guard would have unscrewed itself)
I am going to disassemble the upper tonight and retorque to spec and shoot it again tomorrow. It shot fine at first so I know the barrel is ok (assuming no damage was done by it being loose). Is there anything I should look for when retorquing the barrel to indicate it is a flaw deeper than simply low torque from the factory?
Lessons learned:
Don't modify a rifle without testing it first (I doubt the manufacturer will help me now)
Learn how to perform your own QC and do it, because even quality manufacturers muck it up.
Test your shit before you take it someplace - if I had gone straight to a match or class I would've been on the sidelines.
Loose barrel nuts will cause this and is probably the cause. Tighten the barrel nut and re-install everything. I am going to guess this is a PSA upper since they have a track record of loose barrel nuts.
Here is the rifle in question. Lower bought in 2009 with a brand new unfired 10.5" upper. I have neither disassembled the lower, nor the upper (I did cut off the delta ring assembly and handguard cap but I didn't remove the FSP or the barrel) A little bit of digging will tell you who made the upper, but I will keep it on the DL IAW site rules.
https://i.imgur.com/NfecO9s.jpg
Everything on the rifle has been vetted - FH, optic, BCG, CH, lower, etc except the upper.
I began zeroing it at 100y with the iron sights and immediately noticed the rear sight was all the way to the left for a good zero. This was a yellow flag, but it was shooting nicely so I drove on. I got about 1.5" at 100 yards with 64gr Gold Dots for my confirmation fire - right where I was aiming. I was happy.
I turned on the T2 and started to zero that. The first 10 rounds (about 25 total so far) went ok. I was shooting high right with Wolf Gold. Adjusted the T2 down and left.
That's when the fun started. My groups were then higher and righter. "There's no ****ing way I adjusted that incorrectly, but let's play the game" so I adjusted back twice the amount down and right (to compensate or any amount I might have done wrong)
This was the following target. I think it came out to be about an 18" extreme spread at 100 yards from a sandbag rest.
https://i.imgur.com/KaFs7WI.jpg?1
This was the next target with Speer Gold Dots. The highest 3 rounds were done unsuppressed which caused a POI shift upward, but the rest were suppressed. That's about 7 MOA at 100 yards with quality ammo.
https://i.imgur.com/NsRzeP3.jpg
It also had a failure to fire unsuppressed as the bolt jammed the new cartridge in the neck as it was attempting to feed. For a little perspective, I have not had a failure to fire of any kind in any AR15/M16 I have shot since 2007 when I was a young Lance Coolie in Iraq buying into the "Lube attracts dirt" mantra preached by more senior (and retarded) SNCOs.
Red flag.
At that point I went home. $10 is too much money to spend on 7 MOA groups. I checked the flash hider and the optic at the range. Both were fine.
When I got home I did a more thorough inspection and found this:
https://i.imgur.com/cNo2U3Y.mp4
The barrel nut shot loose on a brand new upper. (It took me a second to realize the nut itself is loose, and if it weren't for the anti rotation tabs/gas tube the hand guard would have unscrewed itself)
I am going to disassemble the upper tonight and retorque to spec and shoot it again tomorrow. It shot fine at first so I know the barrel is ok (assuming no damage was done by it being loose). Is there anything I should look for when retorquing the barrel to indicate it is a flaw deeper than simply low torque from the factory?
Lessons learned:
Don't modify a rifle without testing it first (I doubt the manufacturer will help me now)
Learn how to perform your own QC and do it, because even quality manufacturers muck it up.
Test your shit before you take it someplace - if I had gone straight to a match or class I would've been on the sidelines.
Eurodriver
03-15-19, 18:59
Loose barrel nuts will cause this and is probably the cause. Tighten the barrel nut and re-install everything. I am going to guess this is a PSA upper since they have a track record of loose barrel nuts.
Your guess is actually Likely Many Times incorrect.
If I bought a PSA and this happened I wouldn’t have even made the thread. (Same for a canter FSB)
My guess is that it is an LMT since that was what you were painting in the other thread.
Tighten it all up and I would suggest you still contact then and at least let them know about the issue. Everyone makes mistakes and they may have just had one slip throw the cracks.
And you can always stake the barrel nut to be sure. ;)
Your guess is actually Likely Many Times incorrect.
If I bought a PSA and this happened I wouldn’t have even made the thread. (Same for a canter FSB)
I see what you did there. Your buddy Firefly is gonna be disappointed.
Well hopefully it's not Likely Many Times incorrectly gassed like many of them are.
Your guess is actually Likely Many Times incorrect.
If I bought a PSA and this happened I wouldn’t have even made the thread. (Same for a canter FSB)
My guess is that it is an LMT since that was what you were painting in the other thread.
Tighten it all up and I would suggest you still contact then and at least let them know about the issue. Everyone makes mistakes and they may have just had one slip throw the cracks.
And you can always stake the barrel nut to be sure. ;)
Maybe some red Loctite. :rolleyes:
Damn...at least you got to the root of the problem hopefully without any other issues.
Maybe some red Loctite. :rolleyes:
That works also. :)
MountainRaven
03-15-19, 19:34
Well hopefully it's not Likely Many Times incorrectly gassed like many of them are.
Are we talking Literally More Than enough gas or Less Mass Transiting through the gas system?
Likely More Too much gas. Many I have seen were in the high .070 range.
Are we talking Literally More Than enough gas or Less Mass Transiting through the gas system?
Always fire every weapon in new condition, with zero mods aside from optics (rifle).
Anything else is a potentially huge waste of time and money.
ginzomatic
03-15-19, 20:39
Likely More Too much gas. Many I have seen were in the high .070 range.
Well hopefully it's not Likely Many Times incorrectly gassed like many of them are.
Brutal.
I had such a high opinion of their product for a long time
Sent from my iPhone using Tapatalk
Agreed. Even something as simple as stock rifle/carbine should be checked. I know one particular agency that removes handguards, gas tubes and checks barrel nuts before they are issued due to previous problems with several loose barrel nuts.
Always fire every weapon in new condition, with zero mods aside from optics (rifle).
Anything else is a potentially huge waste of time and money.
Less Mods Today with a brand new rifle.
You may already plan to do this, I would take the nut completely off the threads and take a close look at the threads and the nut to make sure everything is ok, if so torque it down.
It happens. My issue M4 did the same thing, I think my Company had 15 or 20 so it was a bad batch. New guy at the barrel nut torquing station at Colt I guess. Luckily happened in train up so they were all fixed before deploying.
Pro tip. Torque the barrel nut to MAX and then loosen 2 or 3 times. Then reapply a little grease (don't forget the face of the barrel extension) and torque to finish.
crosseyedshooter
03-15-19, 23:58
Man, this thread brings back memories. One of my first complete AR purchases during the last administration was a lightweight profile barrel M4 from a company renown for their QC. The safety selector didn't flip to 90-deg and they wanted the entire rifle back for inspection. Well, I didn't want to give up the rifle, so I upgraded to a BAD-ASS ambi safety which seemed to solve the 90-deg problem. About six months later, I noticed rub marks under the right-side lever and realized that the selector core wasn't centered between the receiver. The detent hole location was drilled out of spec, which wouldn't be a problem for a left-side-only selector. None of my other lowers from this company had the problem and I eventually sold it.
I also have another lower from the same company with an A5 receiver extension that has a stuck bolt release. I shoot left-handed and use my trigger finger to drop the bolt but can't do it with this particular lower out of eight ARs I own. There must be a burr or something catching when the bolt is putting pressure on it. It feels completely normal just fingering it without the bolt applying pressure to the bolt catch. It works when shooting right-handed and doing the palm slap, so I can see how not everyone would consider it a problem.
These small details probably don't show up on any checklist and many not be caught by inspection. I guess my examples are Basic Checking Mistakes compared to your under-torqued barrel nut.
Let Me Tell you that these things happen and a Lot More Than that will deter me from Loving My Team.
Lessons, Mistakes, Takeaways. All part and parcel of Learning More Things.
titsonritz
03-16-19, 02:32
Like Massive Turds
Let Me Tell you that these things happen and a Lot More Than that will deter me from Loving My Team.
Lessons, Mistakes, Takeaways. All part and parcel of Learning More Things.
I see what you did there.
Sent from my iPhone using Tapatalk
My Little Metal Toy is the only non-mixmaster AR I have and I am glad I did not Let More Time go by before I stopped rolling my own. Let Me Tell you, it seems well made and I plan to have Lots More Trigger time with the little carbine. Since Likes Mentioning Trannies says they are good to go I'm not worried.
AndyLate - won the internet today.
titsonritz
03-16-19, 13:49
AndyLate - won the internet today.
Yeah he did, well done.
Eurodriver
03-16-19, 13:55
FWIW I took it to the range today and beat the piss out of it after reassembling it last night.
The torque on the barrel nut was gone. It wasn’t even finger tight.
I did torque 3x and lube the threads with grease when putting it back together.
Today there were failures. Accuracy with Wolf Gold and IMI M193 was acceptable. Gold dots were pretty good. Took it to 200y and was pleased with the results.
Let’s Make This known that any brand can fail and a solid background in AR design (ie an armorers class) is a good insurance policy.
Overall I’m not exactly impressed, I probably wouldn’t buy another one, and I’m annoyed I had this issue in the first place. On the other hand, while it is at the lower level of acceptable accuracy, it is still acceptable and I’ll beat the shit out of it.
Also, lol @ Andy.
I'll confess, I drink the Kool-Aid also...
This is the funniest thread I’ve read on m4. Wish I wasn’t a dummy so I could add something witty
PSA?
BCM?
FWIW I took it to the range today and beat the piss out of it after reassembling it last night.
The torque on the barrel nut was gone. It wasn’t even finger tight.
I did torque 3x and lube the threads with grease when putting it back together.
Do you mean it loosened up again?
I shot my 14.5" LMT carbine today as well, but only to zero the AP PRO. No issues and function is spot on with a H2 buffer, standard action spring.
Eurodriver
03-18-19, 09:23
Do you mean it loosened up again?
I shot my 14.5" LMT carbine today as well, but only to zero the AP PRO. No issues and function is spot on with a H2 buffer, standard action spring.
Nah, it loosened the first time. The second time it shot well and functioned as expected although I will say accuracy is not as good as my SOLGW or BCM equivalents.
I might have to caveat that by saying I am using a milspec LMT trigger whereas the others had BCM PNTs or ALG ACTs though
Straight Shooter
03-18-19, 09:35
Nah, it loosened the first time. The second time it shot well and functioned as expected although I will say accuracy is not as good as my SOLGW or BCM equivalents.
I might have to caveat that by saying I am using a milspec LMT trigger whereas the others had BCM PNTs or ALG ACTs though
My Defender had THE WORST trigger ever..bottomed out my pull gauge so over 10lbs..plus had a horrible "catch" in it. Replaced it with a 4lb Velocity many years ago..the rifle is & has been 100% reliable for over 10 years.
Five_Point_Five_Six
03-18-19, 09:40
This is the funniest thread I’ve read on m4. Wish I wasn’t a dummy so I could add something witty
PSA?
BCM?
Likely More Time is needed for you to reread and figure out the brand. Lots More Truth can be found when reading between the lines. Loose Mechanisms Torqued properly fixed the issues. Loose Machining Tolerances are usually to blame with cheaper budget brands, but Like Mentioned Today, this was from a company with a rep for quality. Likely Monday Troubles.
This thread confuses me. I have Lost Much Time trying to figure it out. I myself had Loose Mechanicals Twice from a particular company. However, I did not Lose Much Time in repairing the issue. I will continue to attempt to read between the lines, but I doubt I will be able to figure it out as I do not have a Lucid Mind Today. Less Mucho Tequilia should give me Lots More Transparency. But then again, I am a Lousy Misanthropic Tramp.
Cheers, Steve
My Defender had THE WORST trigger ever..bottomed out my pull gauge so over 10lbs..plus had a horrible "catch" in it. Replaced it with a 4lb Velocity many years ago..the rifle is & has been 100% reliable for over 10 years.
I swapped in a G2S to replace the factory trigger in my recently aquired LMT lower without even trying it.
Andy
I am just saying per triggers I would pay whatever it took for Bailey Jay to be on Geissele triggers.
She would blaze away with a Super Dynamic Combat, give a wink and say “What do YOU have going on in YOUR lower?”
I also demand she wear the schoolgirl outfit
Like Most Types, I want to avoid the Lazy Man Trap of clever wordplay on internet forums too much.
So Less Meaningless Talk and Lots More Training!
I do Love My Twin Defenders, though. One has the factory 2 stage Lightly Machined Trigger, which is quite good, even side by side with SS? trigger in my brother's rifle. The other one is bog stock, bout the same as any other decent non-enhanced trigger.
This thread reminds me of the Princess Bride:
Spainard: "no more rhyming, I really mean it!"
Giant: "anybody want a peanut?"
If you don’t Love More Trannies, look for Becky, Cindy, and Melissa. Less money and just as good.
Agreed. Even something as simple as stock rifle/carbine should be checked. I know one particular agency that removes handguards, gas tubes and checks barrel nuts before they are issued due to previous problems with several loose barrel nuts.
That is a good idea. Our agency purchased 400 carbines and had issues with loose barrel nuts and loose receiver extension nuts. We purchased 400 carbines from another vendor that had defective rear sight assemblies. It seems like less attention is paid to government contract carbines and rifles than other products sent out the factory door. Department armorers should check them closely before being issued.
Good points. Before I carry a personal weapon, I check it out and if a longarm book it/keep a data journal. This wont deter me from the manufacturer in question (whoever they are) because they really will fix it.
Also T2C, I like your avatar. Like Luke McCain.
I’ve purchased faulty products from almost every higer end firearms manufacturer including HK, FN, BCM, DD, and Colt. I’ve learned that all companies can put out a lemon, it happens. What separates a quality manufacturer is the frequency of out-of-spec products and how the company handles warranty issues. However, with my luck I bet I could purchase an SR-25 and have some kind of issue.
ChattanoogaPhil
03-19-19, 09:55
I guess I must lived a charmed life. The wife's PSA has now gone through two cases of M193 without a hiccup. Of course we're talking about recreation only. Still, the barrel nut has remained in place.;)
https://i.imgur.com/IaU3iBC.jpg
Eurodriver
03-19-19, 10:02
Imma get me a wife so I can “build” her guns, too.
ChattanoogaPhil
03-19-19, 10:07
Due diligence and testing a prospective wife is very important.
Due diligence and testing a prospective wife is very important.
Quality parts are also important.
titsonritz
03-19-19, 11:45
Parts is parts
Not
Imma get me a wife so I can “build” her guns, too.
Whomever bears my yoke is responsible for their own gear.
In Georgia, you got a lot of “shotgun and bolt action” girls who go on about their .270s and 6MMs and Nikon scopes and lack of penis. Or the frumpy cop girls who act like their PSA makes them “one of the guys”
The black girls are moderately better but then you run into the SCCY and Hi Point crowd.
All I want is a tall, fertile Rosa Salazar looking chick with an SR-15. All I want God. You are on notice before I convert to Zoroastrianism....
Whomever bears my yoke is responsible for their own gear.
In Georgia, you got a lot of “shotgun and bolt action” girls who go on about their .270s and 6MMs and Nikon scopes and lack of penis. Or the frumpy cop girls who act like their PSA makes them “one of the guys”
The black girls are moderately better but then you run into the SCCY and Hi Point crowd.
All I want is a tall, fertile Rosa Salazar looking chick with an SR-15. All I want God. You are on notice before I convert to Zoroastrianism....
I hear AOC runs an AAC in secret, but its probably just rumors.
You should scope it out just to be sure.
Imma get me a wife so I can “build” her guns, too.
It doesn’t work. She’d see through it.
I had a similar issue on a Lovely Military Tech rifle, only in the 7.62x51 variety. Got the rifle and the upper was chipped up in several spots (cosmetic). Was willing to overlook that, but had so many FTF trying to zero it that it was near impossible to use the thing. Literally, every 3rd-5th round appeared to be short stroking, even with surplus hot NATO. Sent it back, they replaced the upper, but informed me that these rifles take ~200 rounds to break in and that the issue I was having was normal. Apparently, the manufacturer uses stiff buffer springs, combined with other unique elements that combine to require a decent break-in period.
Welp, kept shooting it, it kept FTF issues... until about 190 rounds. Then, all of the problems seem to have magically went away. Not really pleased, as I had to burn through nearly $100 of ammo to get the rifle to a point it wouldn't fail.
Not sure if these are the same issues you're experiencing or not, but thought I'd toss it out there.
It doesn’t work. She’d see through it.
Nope..... workes too well..... my wife now has 5 ARs and I built them all for her.....and she is very picky..... and now she doesn't let me shoot them or even mess with them.....:nono:
I was listening to an old P&S modcast, and I think it was Mike from SOLGW that mentioned test firing is important because sometimes it takes a few rounds to smooth everything out, even on a well-made gun. But with what you describe, one would imagine the manufacturer would notify ahead to Let Me Think about the purchase.
Nope..... workes too well..... my wife now has 5 ARs and I built them all for her.....and she is very picky..... and now she doesn't let me shoot them or even mess with them.....:nono:
My wife now hates AR’s. I didn’t quite get away with it the first time...
RetroRevolver77
03-20-19, 11:08
Imma get me a wife so I can “build” her guns, too.
Don't, they never appreciate them and then they gravitate toward your most expensive stuff because they are women. My wife claimed my MP5 as hers somehow.
...even with surplus hot NATO...
7.62 NATO is loaded to lower pressures than commercial 308 Win.
Nope..... workes too well..... my wife now has 5 ARs and I built them all for her.....and she is very picky..... and now she doesn't let me shoot them or even mess with them.....:nono:
Mine has two, same deal kind of - one 20" and one 16" I went to swap an optic off her 16" and was told to keep my hands off her rifle.
I can't complain too much, she has been helping me sort and polish brass quite a bit lately.
We’ve gone “full derp” here. You never go full derp.
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