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Posted: 10/12/2016 6:22:51 PM EDT
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Hello
Earlier this summer, around June, I built my first AR. My AR15, chambered in 5.56, has a 16" Radical firearms upper mid length gas impingement with an an Anderson BCG, a spikes lower, an ALG ACT trigger and it's failing to extract the empty casing completely. When a round is fired, the BCG will fully cycle and pick up a new round but the spent casing will remain in the rifle and get jammed sideways against the bolt face. This results in the spent casing sticking half way out of the rifle. I ran an anderson carbine buffer and tried switching to a spikes ST-T2 but the problem persists. All of my mags are magpul. The rifle has about 600 rounds through it with a wide variety of ammunition including american eagle 55 gr., double tap 62 gr., federal bulk 55 gr., remington UMC 55 gr., as well as a few hundred hand reloads all 55 gr. checked with a nogo gauge and found them to be right to spec. I sent the upper to Radical and they called me the day they received it saying the test fired 2 mags without an issue and the upper was sent back to me asap. I have not been able to find any consistency with the jamming issue. For the first 200 rounds or so, this was not a problem. Ive found a post that said this is caused by too much pressure on the BCG through the gas tube but i haven't found a solution to the problem. If anyone has any solutions, it would be much appreciated. Thank you, -Brannon |
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If the bolt will lock back on the last round fired out of a mag, then the rifle is at least full stroking. If you needed confirm such, then single loaded round in a mag, fire the round with a empty mag still and well, and confirm that the bolt locks back on the catch.
If such is the case, then start off by checking the spent cases for signs of too much force being used to extract the spent case from the chamber. Here, you will find that the extractor will bind the rim of the case on extraction, if the problem is that either the rifle is over functioning (bolt unlocking too soon), or could just be a case of the chamber not cleaned correctly during cleaning (chamber brush with CLP by hand used to clean the chamber) or the wrong solvents being used to not only clean the rifle, but to lube is as well. Hence if you are not using a chamber brushing to clean the chamber and say you are using Hopper solvent to clean the chamber and bore, then the problem could be just that Hoppes leaves behind a protective resudue, and it combined with powder fouling is a quick way to chock out the rifle. To break down cleanings (including when you pull the extractor to clean under it during B/C cleanings), Something like Sweets to clean just the rifle bore since it does not take a lot of scrubbing and will not leave behind a sticky residue, Chamber next scrubbed with CLP, then CLP used to clean the rest of the rifle. From here, all the fouled CLP is removed from the rifle, then the upper receiver bearing surfaces are lubed with CLP before the rifle is put into service. As for with the rifle correctly cleaned, including the chamber scrubbed and upper receiver bearing areas CLP lubed, if the rifle is still not extracting the spent case correctly, and no signs of the case rims bent, then suspect that the extractor spring is going weak instead. But the fact that for the first 200 rounds, and then for the manufacturer to test the rig and it ran without problem, do suspect that the issue is a cleaning and lubing problem isntead. |
| I'm going through something similar with a pistol build but mine is probably due to overgassing. My ejection problem was fixed by installing a BCM extractor spring upgrade kit but it still has excessive recoil. Unless your mid seems to have excessive recoil, this probably is not your problem. In addition to the proper cleaning previously suggested I would buy an upgraded extractor spring kit (such as from BCM) that has a stronger spring and insert along with an O ring. You may also need to replace the extractor, inspect it. I would also check the ejector. The ejector should be hard to push down with your fingernail - if it's fairly easy, replace the spring and check the ejector for damage. Regardless, you need to narrow down what the issue is. The replacement parts I suggested shouldn't cost more than $10-20 and they will serve you well even if this isn't the issue. After firing 20 -30 rds, remove the bolt and check it. Are there tiny brass shavings on the face? Check your brass for damage by the ejector and the extractor - if it's overgassed, you'll see where the ejector has clearly indented the brass. Damage by the extractor is harder to see unless you know what you're looking for. Bottom line: I'll bet that replacing the extractor spring components as I specified will fix your problem, if it doesn't, replace the ejector spring. Anderson sells some good stuff but after reviews I've read I have to question their quality control. I'm sure the steel BCG is fine. Replace the parts I suggested. Make sure your BCG is well lubed when you fire it. Did you send the BCG to Radical with the upper when they test fired it? |
| Thank yall for all the suggestions. I was finally able to get to the range after trying some of yall's suggestions. The bolt is locking back consistently on last round. I cleaned the chamber thoroughly before shooting as well. This time, I had 3 out of 50 rounds jam in the same fashion. The only thing left i haven't tried is the BCM extractor upgrade. Could such a small upgrade fix the issue? I'm not quite sure what else could be the problem. |
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