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Posted: 5/15/2013 5:51:44 PM EDT
After replacing my damaged bolt i took to the range to finally test my pistol build. It woud constantly double feed, FTE and trap the used shell casing backwards by the bolt as depicted in the pictures. Setup details below. Any recommendations to ensure reliability? I had planned to run the Phase 5 pigtail gas tube but had fitment issues and at the advice of this forum i ditched it for a standard set up. My first thought is a timing issue, but not sure which route to take to test/solve that.
ELEMENT ARMS NATIONAL MATCH SEMI-AUTO AR-15 BOLT CARRIER IS MACHINED TO PRECISE TOLERANCES WITH LARGER BEARING SURFACES THAN STANDARD CARRIERS. MACHINED OUT OF 8620 STEEL, AND PLATED WITH A PROPRIETARY ELECTROLESS NICKEL/COBALT FINISH, MIL-SPEC GAS KEY (HARD-CHROMED INTERNALLY), ATTACHED WITH GRADE 8 SCREWS PROPERLY TORQUED AND STAKED. THE 5.56/.223 BOLT IS ALSO MACHINED FROM 8620, SHOT-PEENED, MP INSPECTED, AND MANGANESE PHOSPHATED. http://imageshack.us/a/img203/755/imag0054ht.jpg http://imageshack.us/a/img577/4654/imag0013mz.jpg http://imageshack.us/a/img708/354/imag0053y.jpg http://imageshack.us/a/img571/17/imag0018jy.jpg http://imageshack.us/a/img826/1844/imag0016tb.jpg |
| Try running a heavier buffer. H1-3 or the Spikes Series. Shorter barrels have over gassed cycles so running a heavier buffer allows for things to slow down and sync up better. I run H3 buffer on my 11.5'' and it's smooth as silk even with garbage ammo. Also the fact that when you ran hotter ammo it was less reliable leads me to believe it's probably just over gassing and a heavier buffer is required. Sorry my response was put together like a 3 year olds macaroni project, I'm tired haha. |
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After replacing my damaged bolt i took to the range to finally test my pistol build. It woud constantly double feed, FTE and trap the used shell casing backwards by the bolt as depicted in the pictures. Setup details below. Any recommendations to ensure reliability? I had planned to run the Phase 5 pigtail gas tube but had fitment issues and at the advice of this forum i ditched it for a standard set up. My first thought is a timing issue, but not sure which route to take to test/solve that. That happens to me every time I shoot "Independence" 3 rounds max before it jams so that's my last choice of ammo if it's on the shelf. Have you tried the 0-ring around the extractor spring ? |
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you have a carbine buffer now, get a H3 and you can mix and match the weights to get a H1, H2 or the H3 to see what works best. The backward brass and the marks on the ejection port and the brass deflector indicate the brass is hitting the back of the port and bouncing back in. It's pretty much the only way for brass to end up facing the wrong way. Check the bolt face while pulling the charging handle all the way back. The bolt should be about 1/8" or so inside the port. If it is going all the way back and past the port this could be your problem. If so remove the buffer and spring, drop a quarter or two into the buffer tube and reinstall the spring and buffer. Test fire. If this solves the problem you may need to file the buffer tube threaded face to allow another turn in. |
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My 7.5 Noveske frakenrifle runs like a dream with a H3 Buffer, auto carrier, and an extra power buffer spring.
Are you using a brass catcher? I only ask because your first pic looks like one of those mesh bag velcro strap on jobs under the handguard there. Those things are terrible, I've seen them jamb brass back into the action during 3 gun matches and shooting off the bench. |
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My 7.5 Noveske frakenrifle runs like a dream with a H3 Buffer, auto carrier, and an extra power buffer spring. Are you using a brass catcher? I only ask because your first pic looks like one of those mesh bag velcro strap on jobs under the handguard there. Those things are terrible, I've seen them jamb brass back into the action during 3 gun matches and shooting off the bench. We did bring a brass catcher, but it was not used due to the cycling issues. Thank you for the information on the buffers this seems like my next step to get this thing running. |
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Have you checked the bolt travel as I suggested above? The brass bouncing off the rear of the ejection port is the only way it can end up backwards in the port. The brass marks on the deflector indicates that's what is happening. When the handle is pulled all the way back the face of the bolt is about 1/8 of an inch past the ejection port (to the left, towards buffer tube) |
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There is a small roll pin holding the plastic buffer tip in place, simply tap it out and remove. Very simple and yes it is common. This picture does not show the H3 which is 3 tungsten weights. The small discs are rubber pads between the weights. http://imageshack.us/a/img526/8021/buffercontents.jpg Wow, I never really looked into the different buffer weights. Good explanation and pic! Even after knowing quite a bit about the AR platform, there's always something to learn on this forum. |
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That's a problem. The bolt should be 1/8" or so inside the port (towards the chamber). Your cases are bouncing off the rear of the port and back into the chamber. Remove the buffer and spring, drop 2 quarters down your buffer tube and reassemble. Test fire. Thank you I will test this and see if it helps. Not sure when I will get to the range again. What would cause that to happen? Buffer tube not up to spec? Bad spring? |
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Quoted: Quoted: That's a problem. The bolt should be 1/8" or so inside the port (towards the chamber). Your cases are bouncing off the rear of the port and back into the chamber. Remove the buffer and spring, drop 2 quarters down your buffer tube and reassemble. Test fire. Thank you I will test this and see if it helps. Not sure when I will get to the range again. What would cause that to happen? Buffer tube not up to spec? Bad spring? Could be a few things. Your spring could be short, it should be 10 1/8" min. to about 11 1/4" with 37 to 39 coils. The inside depth of the buffet tube should be 7". The bolt carrier could also be a bit short or the buffer itself, does the plastic end look flattened or mashed down? It could have taken a beating. pistols have a much more violent recoil then even a carbine. (sorry, I don't know the exact length of either off hand). Or it could be a combination of any or all, aka tolerance stacking. Best bet is the buffer tube is long. Not a big problem. If you can screw it in more without hitting the tip of the retainer then try that. If it's simply too long you may need to file the face down a bit to get the tube to screw in a bit more. Or if it works for you then simply leave the quarter(s) in the tube. You should also have a heavier buffer in there. I recommend getting the H3 and using the different weights to get one that works best. There is no "right" buffer, the correct one is the one that cycles the action completely and "feels" good (no pounding or sharp, abrupt recoil). Keep us posted. |
| the buffer spring is 10.5 inches long and the buffer tube is approximately 7 and 1/8 inches long. I put three quarters at the end of the buffer tube and now you can just barely see the face of the bolt inside the ejection port. I am hoping to test fire this weekend and report back. Oh also managed to get a heavy buffer to try too. |
| I was able to shoot it this weekend. Ran 120 rounds with only 3 failures! Three quarters in the buffer tube with an H2 buffer. The main failure was the same a backwards round double feed. I also had two rounds fail to fire, looks like a light primer strike but not 100% sure. I ran 60 rounds of .223 and 60 rounds of 5.56 through it slowly and rapidly. Was a great feeling. Not sure where to go from here but thanks everyone for the help. Also rounds seemed to eject between the 2 and 3 oclock position. |
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