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Posted: 11/7/2010 7:49:54 AM EDT
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Ok... So i know there is info on this problem in multiple places... but my search-fu is failing me.
Best friend just got his DD upper from SmartGunner. He is running a RRA BCG in it. And using a complete lower he bought off the EE... supposedly with a Spikes LPK in it, but no real way to tell if thats true. Appears to be an unmarked carbine buffer in it. also this is a carbine length gas system upper. The BCG is not locking back on the last round. I switched out his lower with my extra DPMS lower, with a DPMS LPK in it and a DPMS carbine buffer. And that seems to work fine... locks back on last round everytime. So Im diagnosing this as he needs to get heavier springs in his FCG correct? |
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Quoted:
Sounds like a short stroke issue induced by new parts and lower powered .223 ammo. What ammo were you using? it was not locking back with Federal XM193 55Gr. It did lock back with Silver Bear 62Gr. He is also having a problem with his BCG like.. sticking in the chamber, when he first charges the charging handle it pulls back fine, but after it is slammed back in the second pull of the chargin handle like "sticks" at first and is not easily pulled back. I attributed this to new parts and possibly the RRA BCG being a bit oversized... But i assumed this would loosen up with time. Could that BCG sticking issue have anything to do with this? Even though when i put my DPMS lower on it it cycled fine? |
| Will his bolt lock back manually? I recently changed out my buffer spring and had to cut it down a few rings to get my bolt to hold open, even manually - it was just a hair too long out of the box. If it does lock back manually, beat on the rifle a wee bit..tap the buttstuck on the carpet, hit the side a bit, made sure that it's actually staying. Eliminate the buffer spring first, then move on to other stuff - it's probably the cheapest and easiest to fix. |
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Quoted: Quoted: Sounds like a short stroke issue induced by new parts and lower powered .223 ammo. What ammo were you using? it was not locking back with Federal XM193 55Gr. It did lock back with Silver Bear 62Gr. He is also having a problem with his BCG like.. sticking in the chamber, when he first charges the charging handle it pulls back fine, but after it is slammed back in the second pull of the chargin handle like "sticks" at first and is not easily pulled back. I attributed this to new parts and possibly the RRA BCG being a bit oversized... But i assumed this would loosen up with time. Could that BCG sticking issue have anything to do with this? Even though when i put my DPMS lower on it it cycled fine? Is that with a round in the chamber? If so you have an out of spec chamber, went through it with a RRA .458 socom. |
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Quoted:
Did you use a different magazine when you switched the lowers or was it the same one? Same Mag... actually tried it with a 20 rd PMAG and a 30 Rd PMAG... Dont think magazine is the source of the issue. Quoted:
Will his bolt lock back manually? I recently changed out my buffer spring and had to cut it down a few rings to get my bolt to hold open, even manually - it was just a hair too long out of the box. If it does lock back manually, beat on the rifle a wee bit..tap the buttstuck on the carpet, hit the side a bit, made sure that it's actually staying. Eliminate the buffer spring first, then move on to other stuff - it's probably the cheapest and easiest to fix. Yes it does lock back manually Quoted:
Is that with a round in the chamber? If so you have an out of spec chamber, went through it with a RRA .458 socom. No, the BCG "sticking" issue is unloaded, no magazine, no round in chamber Quoted:
Is his receiver tube lined up properly? (e.g. is the BCG scraping the top of the tube) Clean the snot out of it and lube the bolt, and Star chamber (but NOT the chamber) and cycle the action about a million times. Seems to be lined up correctly, but i wasn't looking for this, so im not entirely 100% sure. His is a Commercial Extension, and the extension on mine is Milspec though. |
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