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Posted: 9/16/2014 1:53:50 PM EDT
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Hello everyone. I've gotten some good information on this site over the last few weeks. However, I'm having a problem that I need help pinpointing the caus. Here is an overview of the build.
PSA lower with PSA lpk that I installed Complete upper from MAS defense with 10.5 barrel chambered in. 223 Wylde PSA FA BCG with charging handle Fluted pistol buffer tube with standard carbine buffer Here is the problem. First round loads fine. Pull the trigger and it fires. Next round is picked up and gets stuck half way into the chamber. I have to pull back the charging handle slightly to release pressure on the round and it drops into the chamber nicely. Seems to happen every 2 or 3 rounds. Different magazines did not help. I used a semi auto BCG from my brother's gun and it seemed to function properly. Only got to shoot about 20 rounds with the SA BCG. Any insight on why this might be happening? It seems like the weight difference between BCG would be minimal. Is that enough to cause short stroking? Any other ideas? This is my first build, so any help is much appreciated. I'll post a link to some pictures of what happens when firing. http://imgur.com/a/reUOd Thanks! |
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I thought that the gas port may be an issue as well. It was tested before being sent out (or so I was told) with no problems after speaking withMAS defense. If it makes any difference, the brass is ejecting right between 3 and 5 o'clock. Some fly pretty far while others stay within 5-6 feet.
Thanks for the tips, I'll keep trying things. Is there a good way to check gas port alignment? The gas key seems to slide nicely over the gas tube as far as I can tell. I don't have anything to compare to, but it slides over easily with a tiny amount of resistance when it first enters. |
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Lets see a few pics of psa bcg.
I'm sure I will hear it but anytime I see a thread concerning something not functioning and it involves a PSA part, that's where I would begin to look. Especially since you say it ran fine with your brothers bcg. 
ETA: Possible under gas problem. Do you have another FA bcg to try it with? |
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Since you have a extra B/C, lets first check to see if the bolt will lock back on the bolt catch. Load just a single round into a mag, insert the mag into the well, charge the mag and fire the single round with the empty mag left in the mag well.
Before you start to test, make sure that the rifle has been correctly cleaned, including using a chamber brush with CLP to clean the chamber, as well the upper bearing areas correctly CLP after cleaning as well. Now with test firings between the two B/C's If the bolt is locking back on the bolt catch correctly (catch in front of the bolt face and not just on the bottom of the carrier), then the rifle is correctly stroking, and weeds a lot of problems. Since you have two B/C, use both for the test in one of the B/C will not lock back the bolt on the catch, and if you deem one B/C is a problem child, then swap the bolts on the two carriers to weed the problem down to just one of the carrier alone. If the problem weeds down to a single carrier, then the problem most likely is that carrier key is leaking on that carrier. If the bolt instead, then it too is out of spec, and best to just send the entire B/C back for warranty replacement. |
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Awesome! Great ideas from everyone. Unfortunately, I will not be able to try switchingbolts and carriers until this weekend, but I will try the suggestions above. One thing I do know is that my FA BCG does work and function in the other gun, which is a S&W M&p 15 rifle.
Thanks again, everyone. I'll try to report back. |
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Quoted:
Since you have a extra B/C, lets first check to see if the bolt will lock back on the bolt catch. Load just a single round into a mag, insert the mag into the well, charge the mag and fire the single round with the empty mag left in the mag well. Before you start to test, make sure that the rifle has been correctly cleaned, including using a chamber brush with CLP to clean the chamber, as well the upper bearing areas correctly CLP after cleaning as well. Now with test firings between the two B/C's If the bolt is locking back on the bolt catch correctly (catch in front of the bolt face and not just on the bottom of the carrier), then the rifle is correctly stroking, and weeds a lot of problems. Since you have two B/C, use both for the test in one of the B/C will not lock back the bolt on the catch, and if you deem one B/C is a problem child, then swap the bolts on the two carriers to weed the problem down to just one of the carrier alone. If the problem weeds down to a single carrier, then the problem most likely is that carrier key is leaking on that carrier. If the bolt instead, then it too is out of spec, and best to just send the entire B/C back for warranty replacement. Just FYI, thanks for the help so far everyone. It seems that my BCG does lock back on an empty mag consistently. Rounds eject right at 3 o'clock. It does seem to work better if there are only a few rounds left in the mag. Full mag malfunctions every 2 rounds while mags I load with ~4 rounds will function perfectly until the empty mag. Hoping I don't have to buy a new BCG, but that might be my next step. |
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