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Posted: 3/23/2014 10:21:30 AM EDT
Hey all, finally got out to test fire my first build the other day and was left disappointed  . I am having failure to extract and 90% of the time have to manually cycle the round out and the other times it will not feed a new round.
I first tried with an Elander mag, figured it could be the culprit so loaded in a trusty pmag and actually fired all 30 rounds without issue, but this was the end of the good times. Next I tried a lancer mag and had failures to extract, so i took all rounds out of the elander and lancers and loaded them up in the pmag and kept having these issues even while using the pmag now. It will not extract the rounds most of the time and if it does it wont feed the next round and I even get the occasional double feed with a live round and the previously fired round stuck in the receiver area. The rifle is my a4 wannabe 
20" BCM government upper PSA lower PSA premium BCG/BOLT ALG ACT trigger BCM gunfighter charging handle RRA A2 stock kit KAC RAS and VFG Ammo used was some herters 55g soft tip 223, Federal AR223 55g and PMC Xtac 5.56 55gr it seemed to be having the issues with all of them indiscriminately. I do have an extra bolt/BCG group here that I could try if that is possibly the issue (didn't have it with me at range), It is the budget BCG from AIMsurplus. Anyways where do I get started on tryin to work the gremlins out of this thing! |
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Sounds to me like you are having a short recoil/undergassed problem, and not a failure to extract.
Failure to extract is when the bolt is not clamping onto the shell casing and pulling the spent round from the chamber. Failure to eject is when the spent round/casing is extracted from the chamber, but is not thrown out of the upper receiver. If your gun was cycling normally, and you had a failure to extract problem, every round fired would result in a jam with a spent casing in the chamber (or partially in the chamber), and a live round partially pushed out of the magazine and jammed against the barrel extension or the rear of the spent casing. With a failure to eject problem, the gun would probably jam with the bolt carrier partially rearward and the spent casing jammed somewhere above the magazine. When a gun is undergassed for whatever reason, the bolt and bolt carrier do not have enough energy from gas pressure to blow the bolt rearward, eject the spent casing, and pickup the fresh round from the magazine. The gun maybe stopped with the spent casing still in the chamber, fully extracted and not ejected, OR fully extracted but not picking up a fresh round. Sounds like your gun does not have the gas necessary to extract and eject the spent casing. Underpowered ammo like Herters can have that problem. Did you assemble the Upper assembly and install the gas block or FSB? In many cases leaks due to improper installation of the gas block causes a gas problem (too loose or improperly located gas block). Or a loose carrier key on the bolt carrier can cause a gas problem. |
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Quoted:
Sounds to me like you are having a short recoil/undergassed problem, and not a failure to extract. Failure to extract is when the bolt is not clamping onto the shell casing and pulling the spent round from the chamber. Failure to eject is when the spent round/casing is extracted from the chamber, but is not thrown out of the upper receiver. If your gun was cycling normally, and you had a failure to extract problem, every round fired would result in a jam with a spent casing in the chamber (or partially in the chamber), and a live round partially pushed out of the magazine and jammed against the barrel extension or the rear of the spent casing. With a failure to eject problem, the gun would probably jam with the bolt carrier partially rearward and the spent casing jammed somewhere above the magazine. When a gun is undergassed for whatever reason, the bolt and bolt carrier do not have enough energy from gas pressure to blow the bolt rearward, eject the spent casing, and pickup the fresh round from the magazine. The gun maybe stopped with the spent casing still in the chamber, fully extracted and not ejected, OR fully extracted but not picking up a fresh round. Sounds like your gun does not have the gas necessary to extract and eject the spent casing. Underpowered ammo like Herters can have that problem. Did you assemble the Upper assembly and install the gas block or FSB? In many cases leaks due to improper installation of the gas block causes a gas problem (too loose or improperly located gas block). Or a loose carrier key on the bolt carrier can cause a gas problem. Quoted:
Sounds to me like you are having a short recoil/undergassed problem, and not a failure to extract. Failure to extract is when the bolt is not clamping onto the shell casing and pulling the spent round from the chamber. Failure to eject is when the spent round/casing is extracted from the chamber, but is not thrown out of the upper receiver. If your gun was cycling normally, and you had a failure to extract problem, every round fired would result in a jam with a spent casing in the chamber (or partially in the chamber), and a live round partially pushed out of the magazine and jammed against the barrel extension or the rear of the spent casing. With a failure to eject problem, the gun would probably jam with the bolt carrier partially rearward and the spent casing jammed somewhere above the magazine. When a gun is undergassed for whatever reason, the bolt and bolt carrier do not have enough energy from gas pressure to blow the bolt rearward, eject the spent casing, and pickup the fresh round from the magazine. The gun maybe stopped with the spent casing still in the chamber, fully extracted and not ejected, OR fully extracted but not picking up a fresh round. Sounds like your gun does not have the gas necessary to extract and eject the spent casing. Underpowered ammo like Herters can have that problem. Did you assemble the Upper assembly and install the gas block or FSB? In many cases leaks due to improper installation of the gas block causes a gas problem (too loose or improperly located gas block). Or a loose carrier key on the bolt carrier can cause a gas problem. +1 sounds good |
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Quoted:
Hey all, finally got out to test fire my first build the other day and was left disappointed . I am having failure to extract and 90% of the time have to manually cycle the round out and the other times it will not feed a new round.
I first tried with an Elander mag, figured it could be the culprit so loaded in a trusty pmag and actually fired all 30 rounds without issue, but this was the end of the good times. Next I tried a lancer mag and had failures to extract, so i took all rounds out of the elander and lancers and loaded them up in the pmag and kept having these issues even while using the pmag now. It will not extract the rounds most of the time and if it does it wont feed the next round and I even get the occasional double feed with a live round and the previously fired round stuck in the receiver area. The rifle is my a4 wannabe
20" BCM government upper PSA lower PSA premium BCG/BOLT ALG ACT trigger BCM gunfighter charging handle RRA A2 stock kit KAC RAS and VFG Ammo used was some herters 55g soft tip 223, Federal AR223 55g and PMC Xtac 5.56 55gr it seemed to be having the issues with all of them indiscriminately. I do have an extra bolt/BCG group here that I could try if that is possibly the issue (didn't have it with me at range), It is the budget BCG from AIMsurplus. Anyways where do I get started on tryin to work the gremlins out of this thing! Well, your description certainly suggests inadequate gas pressure to cycle the bolt carrier group. The most common maladies would be: 1) leak at the junction of the gas tube and front gas block; 2) leak at the gas key, on the bolt carrier; 3) gas rings on the bolt missing or worn. An uncommon, but possible problem is an improperly drilled gas port. And it is fairly common with new builds, especially those being fed low-power ammo, to be inadequately lubricated, with the extra friction slowing the bolt carrier. Lastly, incorrect action springs can cause it: a correct spring should measure 11.24" max, down to 10.125" min. If you have a known-good bolt carrier group available, try that first; if the gun operates properly, the issue lies in the bolt/carrier. HTH |
| Yea I would say i had it pretty lightly lubricated and after taking it apart today it seems pretty dry in there so I will try to be a little more liberal with the lube. The Herters is at least brass cased stuff not the steel, but yes the Herter's and Federal 223's could be light loads, maybe I will stick to the PMC Xtac in it for abit as I believe it is a pretty hot round. I have one spare BCG that I haven't used in anything yet, but I could borrow the one from my SIG M400 that hasn't ever given me any issues and give it a try aswell if the issue persists after trying the better lubrication. |
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Quoted:
Yea I would say i had it pretty lightly lubricated and after taking it apart today it seems pretty dry in there so I will try to be a little more liberal with the lube. The Herters is at least brass cased stuff not the steel, but yes the Herter's and Federal 223's could be light loads, maybe I will stick to the PMC Xtac in it for abit as I believe it is a pretty hot round. I have one spare BCG that I haven't used in anything yet, but I could borrow the one from my SIG M400 that hasn't ever given me any issues and give it a try aswell if the issue persists after trying the better lubrication. X-Tac is right there with Lake City for punch, so the question is, does it choke with X-Tac? If yes, you're looking for a gas leak. Lube-wise, there is no magic bullet, but I've had impressive results with EWL Slip 2000 and Militec. Don't neglect checking the gas rings and action spring. 
Good luck. |
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