User Panel
Posted: 5/13/2020 3:48:33 PM EDT
I recently purchased a prebuilt 18” 7.62 Ultimate Upper and LaRue lower directly from LaRue. I’m really happy with the accuracy. However, I am having severe reliability issues with this rifle.
I fired 40 Federal Gold Medal Match rounds (a mix of 168 and 175 grains) during my first trip to the range. Only 3 of those rounds cycled properly. All of the failures I experienced seemed to be caused by short stroking. The bolt would close behind an empty chamber, or the bolt would begin to strip the next round out of the magazine from the middle of the cartridge causing the bolt to jam. The bolt never locked back after firing the last round in the magazine. So, I gave LaRue customer service a call. LaRue has made 3 attempts to fix this rifle since then. Attempt #1 In the first attempt they promptly sent me a new buffer tube and exchanged my magazines. Unfortunately, this didn’t fix the problem. I fired 20 FGMM rounds and 16 failed to feed due to short-stroking. Attempt #2 I then sent the rifle in and they installed new gas rings and exchanged my magazines again. This didn’t fix the problem either. I fired 14 FGMM rounds and 9 failed to feed due to short-stroking. Attempt #3 I sent the rifle in for the second time, they did “something” and this appeared to fix the problem for the most part. I fired 25 FGMM rounds and only 3 failed to feed due to short stroking. I asked what they did to the rifle and they couldn’t tell me. I thought this was odd, but at this point I was happy the rifle was working somewhat. I didn’t touch the rifle for a few months until this past weekend. I fired a total of 80 FGMM rounds. I experienced 1 failure to feed in the first 20 rounds, but the feeding failures got progressively worse after that. I experienced 41 feeding failures over the last 60 rounds, all due to short stroking. The bolt never locked back after the last round out of 16 magazines (I was only loading 5 rounds per magazine). Continued below... |
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Before I reach out to LaRue customer service again, I wanted to see what I can do to fix this problem on my own. It seems like my rifle is under gassed based on the short stroking and the soft recoil impulse. The action is smooth when I cycle it by hand. The bolt will lock back if I cycle the bolt manually with an empty magazine installed. I noticed that the gas block is canted towards the ejection port by a few degrees after my last range trip. Is this a problem? Unfortunately, I do not know what the gas block alignment looked like after I received the rifle from LaRue after the last repair attempt. The gas block does not seem to be loose at room temperature. I checked the set screws at the bottom of the gas block, they are not noticeably loose. I suspect the gas block or gas tube might be the culprit, but I’d like a second opinion before I start tearing into the rifle.
Any recommendations on what I should look for or try next? I’m at a loss. I have made the following modifications to the rifle: - Installed 7.62 VG6 Precision Gamma Muzzle Break - Installed LaRue rifle length buffer tube with spacer - Installed Magpul PRS stock (Gen 3) Sorry for the long post. I’m hoping that the repair history will be helpful for diagnosis. |
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Why do you assume it’s undergassed?
Did you change the spring when you changed the buffer tube? Where does it spit the brass? Is the brass showing any significant dings/dents anywhere? Is it locking back on the empty mag? When you sent it back I’m sure they checked go/no-go so that should be good. |
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Sorry, had to split the post up. I exceeded the 2,000 character limit with my novel...
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Why do you assume it’s undergassed?
- The bolt is not locking back after firing the last round and the recoil impulse feels really soft. Did you change the spring when you changed the buffer tube? - No. The rifle length tube comes with a spacer. LaRue told me to use the same buffer and spring that came with the Ultimate upper Kit. Where does it spit the brass? - At about 5:00 from what I can remember. Is the brass showing any significant dings/dents anywhere? - No. Is it locking back on the empty mag? - No. |
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I had similar issues with my UU 260 Rem in stock configuration.
Acted as if it was under gassed and was short stroking. I checked the gas block and it was aligned. Larue CS replaced the BCG and has run without issue since. Not sure if the gas key may have been off. |
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I’d just contact larue and send it back in, it is either something in the bcg or the gas system as the short stroking is indicating.
Your options are limited either you mess with it and potentially screw it up or send it back in and wait. |
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If you manually cycle the bolt with the charging handle how does it feel? Any hang up toward the rear of the stroke or at the barrel extension when the bolt interacts?
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Originally Posted By whitesys: I had similar issues with my UU 260 Rem in stock configuration. Acted as if it was under gassed and was short stroking. I checked the gas block and it was aligned. Larue CS replaced the BCG and has run without issue since. Not sure if the gas key may have been off. View Quote A buddy had the same issue with his new factory rifle. They sent a new BCG. Fixed it. |
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If you manually cycle the bolt with the charging handle how does it feel? Any hang up toward the rear of the stroke or at the barrel extension when the bolt interacts?
- The action is smooth when I cycle the bolt manually. I looked for signs of friction at the receiver extension and the inside the buffer tube, but I didn't find anything. |
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Ask them if they replaced the bcg last time.
If they did everything else it could be that. Right now is going to be difficult to get anything done. |
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long shot but I have heard of this and that problem was in the holes for the gas block. I cannot member of the holes in the bb l were a little off as in to small or if it was the holes in the gas block itself. the opening of the holes solved the problem. Just something to consider. good luck. find out the correct sized of both and measure. or look for any obstruction.
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I appreciate all of the suggestions. Is there a way I can determine if the bolt carrier group is the culprit without replacing it? I'd like to do as much as I can before contacting LaRue Customer Service again.
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If there are no signs of wear it’s going to be really hard to diagnose. Sorry, I’ve got nothing other to offer without seeing it in person.
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Originally Posted By DasHammer1337: I appreciate all of the suggestions. Is there a way I can determine if the bolt carrier group is the culprit without replacing it? I'd like to do as much as I can before contacting LaRue Customer Service again. View Quote Get with a buddy who has a running gun, and swap bcg and try it, if possible. |
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On a 308 it may be difficult to diagnose the BCG yourself. With AR15, it's much easier if you have all the tools. Checkout 'Instructor Chad' on YouTube. He has the best diagnostic / autopsy videos I've seen. He checks and inspects everything, although he has all the appropriate Go/No-Go gauges too.
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Have you disassembled the BCG?
Are the gas rings correct? Lubed correctly? |
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Originally Posted By steelworker: Have you disassembled the BCG? Are the gas rings correct? Lubed correctly? View Quote I did disassemble the BCG. Nothing caught my attention, although I'm not sure what I should be looking for. Before my last test fire I aligned the gas rings and applied lube as recommended in the LaRue PredatOBR manual. |
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I had some issues with mine that were similar. The gas tube was the culprit. It was not sealing well to the carrier. You could see it was slightly out of round. The tube should flared at the end to seal with the gas key. Mine was not flare all the way around.
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Originally Posted By DasHammer1337: I appreciate all of the suggestions. Is there a way I can determine if the bolt carrier group is the culprit without replacing it? I'd like to do as much as I can before contacting LaRue Customer Service again. View Quote Know anyone close with a Larue 308/260/6.5CM that you could swap the BCG to see if the issue goes away? I never found out why my UU 260 was acting up - Larue sent a new BCG and that fixed the problem. My bolt and gas rings looked good, the gas block was aligned, and the gas tube looked good. Other than a carrier gas key leak, not sure what else it could have been. |
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LT owes OP a new UU that they have function checked with a full mag.
My .02 |
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I would check gas block alignment and the gas tube first. The fact that you have sent it back several times and they obviously aren’t running it through it’s paces would really run me the wrong way.
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Not really relevant but I had a .224V that was blowing primers. I sent it and and it came back seemingly just covered in oil. I took it out and no malfunctions since. I called in and eventually was told all they did was disassemble it and clean it. They didn't replace or repair anything. But shoots great now.
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Update:
Based on your feedback I decided to investigate the bolt carrier group. I applied WD-40 around the gas key and pressurized the gas key inlet with ~100psi while holding the bolt closed. Lots of bubbles formed on the right and left sides of the gas key indicating a gas leak. I test fired 30 rounds with my friend's LaRue BCG in my rifle. No issues. I then test fired 30 rounds with my BCG in my rifle. Oddly enough, no issues. When I got home, I tried the pressure test with both BCGs and neither produced bubbles. I then cleaned both gas keys with solvent and tried the pressure test again. This time, my BCG produced bubbles but my friend's BCG did not. I then test fired my rifle with my clean BCG and the short-stroking issues came back. I suspect that carbon fouling formed a temporary seal between the gas key and BCG. This might explain the intermittent nature of the short-stroking issues I experienced. I called LaRue and described the testing that I performed. They agreed that the BCG was likely the culprit and decided to send me a new BCG. However, I was warned that this would be their last attempt to fix my rifle. I was on my own if the new BCG did not fix the issue. Interesting. I did not realize LaRue's Lifetime Warranty terminates if they cannot diagnose their own manufacturing defects. They never once offered to exchange my upper throughout this ordeal. I received my replacement BCG 8 days later. I fired 110 Federal Gold Medal Match rounds (175 grain) with the replacement BCG without a single issue. I do not understand why LaRue did not send me a new BCG in the first attempt to fix my rifle given how many of you received new BCGs in response to similar issues. Boggles the mind. My rifle is finally functioning properly. However, it seems that they sent me a blemished BCG for all of my trouble. I'll post more details on this in a separate post. Thanks again for the helpful suggestions. |
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The replacement BCG that I received appears to be a manufacturing reject when compared to my original BCG. The machining on the right side of the BCG is rough. The laser engraving is faint at best. The gas key staking is questionable. This may seem like I am nitpicking as these are largely cosmetic issues. However, if I had wanted to trade off cost for inconsistent quality, I would have purchased my rifle from a different company. I have attached photos comparing my replacement BCG with my friend's BCG below:
Friend's BCG: My replacement BCG: Gas key staking comparison (replacement BCG on top) Image links: Friend's BCG My replacement BCG Gas key staking comparison (replacement BCG on top) What do you guys think? Do you see anything wrong with my replacement BCG or is this what you would expect? |
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My guess is they took one they knew worked and sent that one. Understand your flustrating situation but if it is working now. Your call at this point. Good luck.
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Glad you have it working again.
Larue sent me a new BCG as the first step in troubleshooting - sorry you had to jump thru hoops to get it resolved. BTW - The Colt Maintenance manual describes sealing the gas key with Permatex gasket sealer You can seal the original BCG and cure that leak. |
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You can always e mail the head honcho if you are not happy. I have never herd of larue telling anyone they would no longer help them unless the gun was modified after leaving the factory.
Hopefully they mean they will try one bcg and if that was not it it would have to be sent back? |
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Quoted: Update: Based on your feedback I decided to investigate the bolt carrier group. I applied WD-40 around the gas key and pressurized the gas key inlet with ~100psi while holding the bolt closed. Lots of bubbles formed on the right and left sides of the gas key indicating a gas leak. I test fired 30 rounds with my friend's LaRue BCG in my rifle. No issues. I then test fired 30 rounds with my BCG in my rifle. Oddly enough, no issues. When I got home, I tried the pressure test with both BCGs and neither produced bubbles. I then cleaned both gas keys with solvent and tried the pressure test again. This time, my BCG produced bubbles but my friend's BCG did not. I then test fired my rifle with my clean BCG and the short-stroking issues came back. I suspect that carbon fouling formed a temporary seal between the gas key and BCG. This might explain the intermittent nature of the short-stroking issues I experienced. I called LaRue and described the testing that I performed. They agreed that the BCG was likely the culprit and decided to send me a new BCG. However, I was warned that this would be their last attempt to fix my rifle. I was on my own if the new BCG did not fix the issue. Interesting. I did not realize LaRue's Lifetime Warranty terminates if they cannot diagnose their own manufacturing defects. They never once offered to exchange my upper throughout this ordeal. I received my replacement BCG 8 days later. I fired 110 Federal Gold Medal Match rounds (175 grain) with the replacement BCG without a single issue. I do not understand why LaRue did not send me a new BCG in the first attempt to fix my rifle given how many of you received new BCGs in response to similar issues. Boggles the mind. My rifle is finally functioning properly. However, it seems that they sent me a blemished BCG for all of my trouble. I'll post more details on this in a separate post. Thanks again for the helpful suggestions. View Quote BTW @DasHammer1337 Thanks for taking the time to diagnose this issue - always wondered what was causing the issue but sent the original BCG back to LT before I thought to test it for a leak. |
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Quoted: You can always e mail the head honcho if you are not happy. I have never herd of larue telling anyone they would no longer help them unless the gun was modified after leaving the factory. Hopefully they mean they will try one bcg and if that was not it it would have to be sent back? View Quote Agreed, it kinda pains me to see that he was told something that contradicts the known if you aint happy warranty. Not knowing the full and correct story I just give the benefit of the doubt. Knowing how generous LT is ..... |
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Quoted: Glad you have it working again. Larue sent me a new BCG as the first step in troubleshooting - sorry you had to jump thru hoops to get it resolved. BTW - The Colt Maintenance manual describes sealing the gas key with Permatex gasket sealer You can seal the original BCG and cure that leak. View Quote Unfortunately, I had to exchange my original BCG for the replacement BCG. I had read about the Permatex gasket sealer. I was afraid to apply the sealer on my own for a couple of reasons. I don't have a gas key staking jig and I was worried that I would void the warranty if I had removed the gas key on my own. |
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Quoted:However, I was warned that this would be their last attempt to fix my rifle. I was on my own if the new BCG did not fix the issue. Interesting. I did not realize LaRue's Lifetime Warranty terminates if they cannot diagnose their own manufacturing defects. They never once offered to exchange my upper throughout this ordeal. View Quote Unacceptable garbage response from LT. |
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Quoted: Agreed, it kinda pains me to see that he was told something that contradicts the known if you aint happy warranty. Not knowing the full and correct story I just give the benefit of the doubt. Knowing how generous LT is ..... View Quote I too gave them the benefit of the doubt, but there is a limit. After their first attempt to fix my upper they offered a refund saying that "troubleshooting the upper may not be worth their time". This was disheartening to hear after waiting 4 months for what I had thought was a solid investment. I realize that the Ultimate Upper Kit likely doesn't generate as much profit as a factory built rifle, but $1,721.16 is still a large investment for me. I did not want to get back in line for another upper. I gave them the benefit of the doubt and trusted that they could diagnose and fix the issue. This experience is not consistent with past experiences I have had with LaRue. I bought my upper with confidence thinking that LaRue would back me up if any issues should arise. Clearly this particular case is an exception, but a notable one. My take away from this experience is: LaRue provides great products with good customer service on average. If you want to avoid experiences like mine, it might be in your best interest to do as much research and troubleshooting on your own before engaging with customer service; even if that means you have to become an "expert" in direct gas impingement systems. |
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That is too bad that the OP has had to go through all this just to get a functioning upper.
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Quoted: I too gave them the benefit of the doubt, but there is a limit. After their first attempt to fix my upper they offered a refund saying that "troubleshooting the upper may not be worth their time". This was disheartening to hear after waiting 4 months for what I had thought was a solid investment. I realize that the Ultimate Upper Kit likely doesn't generate as much profit as a factory built rifle, but $1,721.16 is still a large investment for me. I did not want to get back in line for another upper. I gave them the benefit of the doubt and trusted that they could diagnose and fix the issue. This experience is not consistent with past experiences I have had with LaRue. I bought my upper with confidence thinking that LaRue would back me up if any issues should arise. Clearly this particular case is an exception, but a notable one. My take away from this experience is: LaRue provides great products with good customer service on average. If you want to avoid experiences like mine, it might be in your best interest to do as much research and troubleshooting on your own before engaging with customer service; even if that means you have to become an "expert" in direct gas impingement systems. View Quote Yeah I dont like to see it go that direction. Larue sells the UU at a super silly good price and they do so because it frees up man power($$$$) and time($$$$) and I think they get a point where the little profit that is there is gone and they have gone negative. They had to cost/benefit it and they can not keep taking losses is my guess. I hope that upper does will into the distant future and you can just enjoy it from here on. |
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