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Posted: 1/4/2016 11:36:54 PM EDT
| Built my first AR15 from scratch and put 40 - 50 rounds through it before I started having issues. I can load the magazine and fire the round but it doesn't get ejected. Simply put I cannot fire in Semi-Auto. Every time I fire I have to recharge the weapon. My first thought was that something is wrong with the gas tube/block. It is a direct impingement system. Any suggestions or ideas would be appreciated. Thanks! |
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Knowing what piston system would help, since may be a simple as a gas leak from the barrel port to the piston block, or in the case of a set screw type block, loctite not used on the screws with the barrel dimpled for the set screws, hence the block drifted forward away from the barrel shoulder to block the gas flow instead.
If a bolt on type block on the carrier, then could be a broken bolt that is allowing the carrier block to rise up and wedge against the charging handle slot. Or even just a bend pistol rod that is binding up against the through channel in the upper receiver/ rod binding against the barrel nut spine or through channel in the case of float tube. Next, in the case of an adjustable block and a new barrel, could be either a bore bur or even shavings off the bullet on a new gas port that has clogged up the passages in the adjustable block. Lastly, did you fully clean the barrel chamber with a chamber brush with CLP to start with to remove any storage grease/debris, and did you lube the upper receiver bearing areas with CLP as well? Hence even with a pistol gas system, you still need to lightly lube the upper receiver bearing area's with CLP so the cleaning agent in the CLP can help combat the fouling that will be coming from the spent case extracting from the chamber into the action. |
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Quoted:
Built my first AR15 from scratch and put 40 - 50 rounds through it before I started having issues. I can load the magazine and fire the round but it doesn't get ejected. Simply put I cannot fire in Semi-Auto. Every time I fire I have to recharge the weapon. My first thought was that something is wrong with the gas tube/block. It is a direct impingement system. Any suggestions or ideas would be appreciated. Thanks! Your post is unclear Is the case not being extracted from the chamber? Or is it being extracted, but not ejected? There is a big difference between the two problems |
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Quoted:
Check to OP Dano, it's a DI not piston. 
Got it, and was having a off night. JoshuaEpps, have you check for leaks of the gas block to the barrel and gas tube? Also, have you checked to make sure that the carrier key is not leaking from the top of the carrier? With 40 rounds, and then having problems, would suspect a gas leak problem at hand with something coming loose. As for the quick way to check the the gas block, CLP around the front and back of it to the barrel ,some around the gas tube entering it, then with a piece of tube on the end of the gas tube in the upper receiver with 100lb of air pressure will show you if you have leaks (read did not use loctite on the block set screws). As for the B/C, CLP around the base of the key, hold the bolt in, then pressure through the front of the key. |
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Quoted:
Built my first AR15 from scratch and put 40 - 50 rounds through it before I started having issues. I can load the magazine and fire the round but it doesn't get ejected. Simply put I cannot fire in Semi-Auto. Every time I fire I have to recharge the weapon. My first thought was that something is wrong with the gas tube/block. It is a direct impingement system. Any suggestions or ideas would be appreciated. Thanks! That same problem happened to me. My issue was solved by finding out my gas key attached to the bolt had a gas leak. I just went ahead and bought a new carrier with gas key already attached from the Brownells catalog saving what parts I could (bolt, firing pin etc). What happens is that the key is sealed allowing your bolt to function until the gas key gets really hot during the firing phase. As it gets hot the two parts expands breaking the seal allowing gas to escape. If your on a budget go to any parts catalog like Midway or Brownells and order new gas key bolts and get a small tube of Permatex gas seal and tighten those bolts down. I can't say how much to torque them though. Good luck in your rifle. Impala 
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Kind of over kill to solve a key leak problem with a whole new carrier.
The key bolts can be removed and throw away (never re-use key bolts), the bottom of the key lapped flat on a lapping plate, then lap the key against the top of the carrier to resolve that "flats" problems if needed, then just reinstall the key with new key bolts (37inlb of torque, and the key metal staked into the side of the bolt head spines). If you want to go the extra step, then apply a light coat of Red loctite between the key and carrier when the key is installed, and when the loctite dries, it forms a thin gasket between the two surfaces to solve any leak problems that where not solved with lapping instead. To note, when you pull the key, it always a high ring ridge around one of the channels that is the problem of why the two are not matting leak free together from the start. Most of the time, it a ridge or two on the bottom of the carrier, but is can be ring ridges around the channels on the carrier surfaces as well. |
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Quoted:
Kind of over kill to solve a key leak problem with a whole new carrier. The key bolts can be removed and throw away (never re-use key bolts), the bottom of the key lapped flat on a lapping plate, then lap the key against the top of the carrier to resolve that "flats" problems if needed, then just reinstall the key with new key bolts (37inlb of torque, and the key metal staked into the side of the bolt head spines). If you want to go the extra step, then apply a light coat of Red loctite between the key and carrier when the key is installed, and when the loctite dries, it forms a thin gasket between the two surfaces to solve any leak problems that where not solved with lapping instead. To note, when you pull the key, it always a high ring ridge around one of the channels that is the problem of why the two are not matting leak free together from the start. Most of the time, it a ridge or two on the bottom of the carrier, but is can be ring ridges around the channels on the carrier surfaces as well. Dano523, Yeah some may say it's over kill but that's what Idid and the issue got solved.I did it that way to eliminate every part of my human error if I decided to attempt a repair. My method may have been more expensive but it got the job done. Impala
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So what did you do with the old carrier????
Hence manufacturer would have replace it for free with one that the key was not leaking, or could have solve the problem with the manufacturer just sending new key bolts to reinstall the key after lapping instead (or just buy new key bolts for a few dollars if the manufacturer is not reachable). Hence there are some small parts that is nice to have if you loss them during a detail strip, but a carrier is just not one of the items that most people will wear out on a semi auto rig in their life time instead (put it up there with a chrome lined barrel as well). 
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