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[ARCHIVED THREAD] - Loose Gas Key (Page 1 of 2)
Posted: 4/5/2015 1:51:10 AM EDT
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Was shooting with some friends today and after a couple rounds my gun went bang, click, rack the bolt, bang, click and so on and so forth. When I got home I inspected the BCG and found that the gas key had a wobble seperate from the BCG.
Now how can I fix this or do I need to get a new BCG? My AR is a DPMS and Ive put 500-1500 rounds through it. |
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But ARFCOM keeps telling me that all ARs are the same and that people who buy Colt, LMT, BCM, Daniel Defense, and Noveske are just paying for the name to the battle cries of "my _____ brand shoots just as good as your colt. 
The people that say that are just trying to justify their subpar purchase. Op, i would just buy a new quality carrier, there are plenty of them that come up for sale on the EE. Like this one for example, not my ad but i did buy some from that seller. http://www.ar15.com/forums/t_7_22/1419513_.html |
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But ARFCOM keeps telling me that all ARs are the same and that people who buy Colt, LMT, BCM, Daniel Defense, and Noveske are just paying for the name to the battle cries of "my _____ brand shoots just as good as your colt.
Of course. No one ever has trouble with the mentioned brands. Perfection is wonderful. With many rounds down range, I haven't even had a slight glitch with my DPMS but that doesn't mean it's any good. |
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I would install a new screw with red Loctite, and stake both screws. Oh, and ignore the haters. Quoted:
I would install a new screw with red Loctite, and stake both screws. Oh, and ignore the haters. Red Loctite (271) will fail at the temperature the screws reach. IF you are going to use Loctite, you need to use 2620 
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Take the gas key off and clean the matting surfaces. Apply a little red lock tight to matting surfaces as a sealer. Install new screws with lock tight and stake em. The correct sealant for the mating surface is Permatex Aviation Form-A-Gasket #3 
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Can we get a pic of said bolt carrier group and gas key? Is this a factory DPMS complete rifle or a frankengun on a Dpms lower? Just curious. 
It's a factory DPMS rifle, it's my first AR ever and all that I could afford. I'm really considering buying a new, more quality carrier. I'm planning on getting a new trigger too so I figure I might as well replace the carrier while I'm at it. |
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The people that say that are just trying to justify their subpar purchase. Op, i would just buy a new quality carrier, there are plenty of them that come up for sale on the EE. Like this one for example, not my ad but i did buy some from that seller. http://www.ar15.com/forums/t_7_22/1419513_.html Quoted:
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But ARFCOM keeps telling me that all ARs are the same and that people who buy Colt, LMT, BCM, Daniel Defense, and Noveske are just paying for the name to the battle cries of "my _____ brand shoots just as good as your colt.
The people that say that are just trying to justify their subpar purchase. Op, i would just buy a new quality carrier, there are plenty of them that come up for sale on the EE. Like this one for example, not my ad but i did buy some from that seller. http://www.ar15.com/forums/t_7_22/1419513_.html  I had a DD gas key come loose a couple weeks ago. I don't post about it cause shit happens. Get new screws and re-stake the mo'fo. I've seen Colt and FN rifles shit the bed, every machine breaks. The more you practice, the more you train, the more likely you are to suffer a failure. Its a fact of life and there isn't a brand out there immune to that simple fact of life. Theres a reason AR15.com has threads like "What parts break in a carbine course".
I wish I had pictures of the M4 parts bin from one of my old units. It was a trunk sized box full of shit Colt and FN parts. OP, DSG has a great supply of parts. Go to Hobby Lobby and buy the see through organizers that are often used as a fishing lure box and fill with new spare parts. You use an AR like it meant to be used, you're gonna break and wear shit out. |
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Remove the key and dispose of the screws. Clean both the top of the carrier and the bottom of the key thoroughly, and degrease both surfaces. Apply Permatex on the mating surfaces, then install two new screws and torque to spec (35 - 40 inch pounds). Then stake the screws to keep them from moving.
Proper staking doesn't require any special tools. You stake to move metal from the key into the knurling on the screw head. The TM calls for field staking to displace 0.025" of material, and it should not cause any upward or outward displacement of metal. (This is on page 3-28 of TM 9-1005-319-23&P linked on the ARFCOM manuals page.) The TM procedure calls for three stakes with a center punch on each screw. ALL the stake is supposed to do is push metal into the grooves on the screw head so that it can't move. Anything more isn't needed, and a lot more is detrimental to the screw head. Sometimes it's also damaging to the key. |
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Was reading articles in the armalite.com library. One there on carrier key screw tension. See tech notes, #47
Basically, torque value should be 55 inch pounds, they say. ARticle is a Quick Read. http://www.armalite.com/Categories.aspx?Category=35e8a0b0-7e71-4af3-b335-53f4a7dc8f08. |
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Was reading articles in the armalite.com library. One there on carrier key screw tension. See tech notes, #47 Basically, torque value should be 55 inch pounds, they say. ARticle is a Quick Read. http://www.armalite.com/Categories.aspx?Category=35e8a0b0-7e71-4af3-b335-53f4a7dc8f08. There's the old spec in the US TM which is 35-40 INCH pounds and then there's the newer US TM spec which is 50-59 INCH pounds. The Colt Canada spec that I quoted above, lands about in the middle. I wish they wouldn't do that. |
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Those screws are not regular Grade 8 cap screws. They are harder, than hardware store grade 8 bolts. Pay attention to the torquing requirements. Grade 8 Socket Head Cap Screws are no longer a recognized U.S. standard, they haven't been for a LONG time! If you purchase Socket Head Cap Screws that are labeled Grade 8, chances are they are "off shore" manufactured. The Correct standard is ASTM-A574 ASTM-A574 is STRONGER than the old Grade 8 standard. |
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https://www.flickr.com/photos/129057565@N08/16856439738/ It's a factory DPMS rifle, it's my first AR ever and all that I could afford. I'm really considering buying a new, more quality carrier. I'm planning on getting a new trigger too so I figure I might as well replace the carrier while I'm at it. Quoted:
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Can we get a pic of said bolt carrier group and gas key? Is this a factory DPMS complete rifle or a frankengun on a Dpms lower? Just curious. https://www.flickr.com/photos/129057565@N08/16856439738/ It's a factory DPMS rifle, it's my first AR ever and all that I could afford. I'm really considering buying a new, more quality carrier. I'm planning on getting a new trigger too so I figure I might as well replace the carrier while I'm at it. By stating you are going to get a more quality carrier, I assume you mean a more expensive one. Remember they only make 2 different kinds of machines. Those that have broken and those that are going to. Spending more money isn't always the answer. I know they say "You get what you pay for." Not always. Another old saying - "There's a sucker born every minute." That is a pretty uncomplicated and inexpensive fix. By the way. Do you have a warranty? |
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Get a new BCG if you like but unless your key is damaged, its really not necessary. I'd just do as some of the others said and clean your key, get correct new screws, use Permatex, re-torque, stake, resume shooting. Enjoy your AR.
Not all ARs are the same but that doesn't mean yours is a piece of shit. Sounds like it was working fine for you up till now. Things break. There is likely a lot of life in your BCG. Look at this as an AR maintenance learning opportunity. I would still buy a new BCG though. Then start getting the rest of the parts to go with it for your next AR.
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Grade 8 Socket Head Cap Screws are no longer a recognized U.S. standard, they haven't been for a LONG time! If you purchase Socket Head Cap Screws that are labeled Grade 8, chances are they are "off shore" manufactured. The Correct standard is ASTM-A574 ASTM-A574 is STRONGER than the old Grade 8 standard. Quoted:
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Those screws are not regular Grade 8 cap screws. They are harder, than hardware store grade 8 bolts. Pay attention to the torquing requirements. Grade 8 Socket Head Cap Screws are no longer a recognized U.S. standard, they haven't been for a LONG time! If you purchase Socket Head Cap Screws that are labeled Grade 8, chances are they are "off shore" manufactured. The Correct standard is ASTM-A574 ASTM-A574 is STRONGER than the old Grade 8 standard. The point was, in any case, don't use hardware store bolts... You need to be sure you are getting screws made to NAS1352, A574 or other screws known to have 180 ksi ultimate tensile and a hardness of HRc 39 to 45 ... Oh, and there are still 130,000 150,000 psi screws/bolts out there, and still made in the US. ASTM A354 BD and SAE J429, for example. [edit: fat finger that] |
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I have 1800rds down range with my Youngs Mfg bcg. No staking, with some form of red loctite between gas key and carrier.
Gas key still very tight. Only malfunctions were failure to feeds caused by a heavy buffer spring. I switched from midlength to rifle length and started having short stroking issues. Staking is only needed when your rifle will see real combat, or to deal with other subpar quality control issues. If everything is done correctly, you don't need staking. Eta:  Staking is good assurance. I've debated doing it or not, but I'm not paying someone to do one, nor am i going to buy the tool for it. And I'm not sure I'm comfortable taking a chisel to it just yet.
What other options for the DIY stake job? |
| Not to sound like an ass here, but there is NO failure temperature for staking. If you need to remove the key, you'll have to replace the screws, whether you staked them in, stuck them in with Rockset, or kept them in with duct tape. I do not know a real reason not to stake a gas key. I know a lot of people "prefer not to," but that's not a reason, it's a preference. |
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Quoted:
The people that say that are just trying to justify their subpar purchase. Op, i would just buy a new quality carrier, there are plenty of them that come up for sale on the EE. Like this one for example, not my ad but i did buy some from that seller. http://www.ar15.com/forums/t_7_22/1419513_.html Quoted:
Quoted:
But ARFCOM keeps telling me that all ARs are the same and that people who buy Colt, LMT, BCM, Daniel Defense, and Noveske are just paying for the name to the battle cries of "my _____ brand shoots just as good as your colt.
The people that say that are just trying to justify their subpar purchase. Op, i would just buy a new quality carrier, there are plenty of them that come up for sale on the EE. Like this one for example, not my ad but i did buy some from that seller. http://www.ar15.com/forums/t_7_22/1419513_.html +1 |
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Not to sound like an ass here, but there is NO failure temperature for staking. If you need to remove the key, you'll have to replace the screws, whether you staked them in, stuck them in with Rockset, or kept them in with duct tape. I do not know a real reason not to stake a gas key. I know a lot of people "prefer not to," but that's not a reason, it's a preference. +1 I've changed my mind as to using Loctite 2620 because IF I shear off a screw it's going to be a bitch to remove it when it's set with Loctite rated at 650 degrees. Proper torque, proper staking will ensure the screws stay in place. |
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So this happened.... 
Colt, "C" marked M16 carrier in my 12.5" upper. It was not holding back on the last round. I did some part swapping trouble shooting and with a different bolt the upper worked fine. When I took the bolt apart, I heard a rattle, and noticed that the key was loose. Put an Allen wrench into the front screw and it spun freely. I ordered a new key and screws from Bravo Co. $40 for Loctite 2620 is ridiculous. F that. Does anyone use Permatex 82180 Black on the surface between key and carrier? Permatex 24026 Red is rated to 450F. Would that be ok for the screws? |
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So this happened.... http://i1353.photobucket.com/albums/q673/Mjollnir_458/IMG_3451_zpsiglmoi9b.jpg Colt, "C" marked M16 carrier in my 12.5" upper. It was not holding back on the last round. I did some part swapping trouble shooting and with a different bolt the upper worked fine. When I took the bolt apart, I heard a rattle, and noticed that the key was loose. Put an Allen wrench into the front screw and it spun freely. I ordered a new key and screws from Bravo Co. $40 for Loctite 2620 is ridiculous. F that. Does anyone use Permatex 82180 Black on the surface between key and carrier? Permatex 24026 Red is rated to 450F. Would that be ok for the screws? It would melt just like any red threadlocker. JUST STAKE THE SCREWS and they won't lossen. |
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OK, but... is there a way to do that properly without buying a $80 tool? Quoted:
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It would melt just like any red threadlocker. JUST STAKE THE SCREWS and they won't lossen. OK, but... is there a way to do that properly without buying a $80 tool? I posted this on April 5, on page one of this thread: Quoted:
The TM calls for field staking to displace 0.025" of material, and it should not cause any upward or outward displacement of metal. (This is on page 3-28 of TM 9-1005-319-23&P linked on the ARFCOM manuals page.) The TM procedure calls for three stakes with a center punch on each screw. ALL the stake is supposed to do is push metal into the grooves on the screw head so that it can't move. Anything more isn't needed, and a lot more is detrimental to the screw head. Sometimes it's also damaging to the key. It doing it according to the Army's Technical Manual's instructions isn't "PROPERLY," then nothing is. WAY too many people think you have to mutilate parts to "properly stake" gas key screws. That's 100% wrong. Go to the manual I linked, go to page 3-28 and read. |
| I have used an automatic center punch a few times to stake the screws per the TM instead of a standard punch and hammer. Works fine. I stake the castle nuts on the receiver extension the same way. Automatic center punches can be found at Home Depot for @ $15. You have to "click" them repeatedly to get the desired depth and amount of material moved, but it is a bit easier than using a hammer and punch IMHO. |
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I have used an automatic center punch a few times to stake the screws per the TM instead of a standard punch and hammer. Works fine. I stake the castle nuts on the receiver extension the same way. Automatic center punches can be found at Home Depot for @ $15. You have to "click" them repeatedly to get the desired depth and amount of material moved, but it is a bit easier than using a hammer and punch IMHO. I think I'll go pick one of those up. I don't trust my coordination enough to use a hammer and I don't have a spare $80 for one of those staking tools. 
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Stay away from the locktite and gas seal non sense, replace the key and screws, check the torque specs for the screws, torque the screw, restake, and done.
For the dipshits that put down people for buying military grade firearms and vice versa. People buy colt lmt bcm because the stuff last long because it is properly built, that's it. And if your carrier ran fine before the key screw broke no big deal replace the stuff and move on. |
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Stay away from the locktite and gas seal non sense, replace the key and screws, check the torque specs for the screws, torque the screw, restake, and done. For the dipshits that put down people for buying military grade firearms and vice versa. People buy colt lmt bcm because the stuff last long because it is properly built, that's it. And if your carrier ran fine before the key screw broke no big deal replace the stuff and move on. What you refer to as "gas seal non sense" is a REQUIRED procedure in the TDP and is standard on Colt's |
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What you refer to as "gas seal non sense" is a REQUIRED procedure in the TDP and is standard on Colt's Quoted:
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Stay away from the locktite and gas seal non sense, replace the key and screws, check the torque specs for the screws, torque the screw, restake, and done. For the dipshits that put down people for buying military grade firearms and vice versa. People buy colt lmt bcm because the stuff last long because it is properly built, that's it. And if your carrier ran fine before the key screw broke no big deal replace the stuff and move on. What you refer to as "gas seal non sense" is a REQUIRED procedure in the TDP and is standard on Colt's TM 9-1005-319-23&P, WP 0013, page 13-2 - Assembly (of the bolt carrier) To paraphrase: "Put the key on, torque the two screws to 50 to 58 in-lbs, stake." You're done. |
[ARCHIVED THREAD] - Loose Gas Key (Page 1 of 2)
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