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Posted: 2/6/2024 5:38:55 PM EDT
[Last Edit: 50dan]
I built an Aero 308 with a Wilson Combat 18” barrel, matching WC gas block, rifle length gas tube, and it has a Magpul PRS stock. I can only manually chamber a round, fire it, then it will not eject or feed next round. I think the issue is my buffer setup. My buffer tube is like 9-3/16” deep and I’m using a rifle length recoil spring and a 5.36oz rifle buffer weight that is 5-1/4” long. Should I be using the shorter buffer weight like the AR15 style standard carbine length buffer weight instead of the longer 308 buffer weight? I have a carbine buffer weight that is 3-1/4” in length.
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[#1]
Check the extractor.
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[#2]
The gas port on my 16” WC .308 barrel needed to be enlarged to .085 for the gun to cycle reliably.
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[Last Edit: 50dan]
[#3]
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[Last Edit: Homesteader375]
[#4]
Since a PRS mounts to a rifle length receiver extension, unless you heavily modified something, it should run rifle length buffer and spring. The receiver extension, not the stock, dictates this.
Does the BCG not move at all? I'd start examining gas. GB alignment, leak check everything, gas port size. It hand cycling pretty well rules out the lower and FCG interfering with the BCG. ETA: posted this missing the fact that this is a .308 gun. Shorty buffer is correct for a .308 gun, no rifle length buffer. |
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[#5]
What bcg are you using?
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[#6]
Originally Posted By Homesteader375: Since a PRS mounts to a rifle length receiver extension, unless you heavily modified something, it should run rifle length buffer and spring. The receiver extension, not the stock, dictates this. Does the BCG not move at all? I'd start examining gas. GB alignment, leak check everything, gas port size. It hand cycling pretty well rules out the lower and FCG interfering with the BCG. View Quote An AR-15 rifle length buffer in an AR-15 rifle buffer tube will not allow a .308 bolt carrier to move far enough to the rear to feed. |
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Death to quislings.
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[#7]
Originally Posted By backbencher: An AR-15 rifle length buffer in an AR-15 rifle buffer tube will not allow a .308 bolt carrier to move far enough to the rear to feed. View Quote This above, You need to use a standard length carbine buffer in a rifle tube or A5 length tube for a AR10 or a shortened AR10 buffer if using a carbine length RE. |
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[#8]
Originally Posted By backbencher: An AR-15 rifle length buffer in an AR-15 rifle buffer tube will not allow a .308 bolt carrier to move far enough to the rear to feed. View Quote I swear 4:30 am posting is as bad as drunk posting. I somehow missed that this was a .308 gun. Forget my retardation and carry on. |
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[#9]
Originally Posted By Homesteader375: I swear 4:30 am posting is as bad as drunk posting. I somehow missed that this was a .308 gun. Forget my retardation and carry on. View Quote View All Quotes View All Quotes Originally Posted By Homesteader375: Originally Posted By backbencher: An AR-15 rifle length buffer in an AR-15 rifle buffer tube will not allow a .308 bolt carrier to move far enough to the rear to feed. I swear 4:30 am posting is as bad as drunk posting. I somehow missed that this was a .308 gun. Forget my retardation and carry on. It gets more entertaining w/ the AR-15 receiver length .308s, w/ folks getting pissed Ruger cheaped out & only used a single screw on the gas key. |
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Death to quislings.
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[#10]
BCG is a Toolcraft…
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[#11]
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[#12]
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"The credit belongs to the man who is actually in the boogaloo, whose face is marred by pixels and ink and cheetos.”,
Teddy the Toad, (w,stte), "The Derpmen" |
[#13]
Originally Posted By QtrHorse: This above, You need to use a standard length carbine buffer in a rifle tube or A5 length tube for a AR10 or a shortened AR10 buffer if using a carbine length RE. View Quote View All Quotes View All Quotes Originally Posted By QtrHorse: Originally Posted By backbencher: An AR-15 rifle length buffer in an AR-15 rifle buffer tube will not allow a .308 bolt carrier to move far enough to the rear to feed. This above, You need to use a standard length carbine buffer in a rifle tube or A5 length tube for a AR10 or a shortened AR10 buffer if using a carbine length RE. I’m using a rifle length buffer tube, weight and spring for the Magpul PRS. |
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[Last Edit: QtrHorse]
[#14]
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[Last Edit: Dano523]
[#15]
And on PRS butt stock, are you using a shorter A1 bolt, and not the longer A2 that would be protruding into the receiver extension void area?
As for bolt not moving at all, either gas leak, or gas blockage. Hence some gas blocks are set up to use forearm clips, some are not, so don't just slam the gas block all the way back against the shoulder, until you messure distance from shoulder to gas port, then same on gas block, to see if it needs to be gapped off the barrel shoulder of not to align with the barrel gas port. As for gas leakage, CLP around back of carrier key, hold the bolt in wards, then pressurize the front of the key to make sure it not leaking against the top of the carrier surface. Same for gas block to barrel and tube, and pressurize gas tube from withing the receiver. Last one, there is dmps/stoner spec for 308, then armalite in 308, and the two are not the same. So figure out what upper parts in play, and make sure that barrel is same spec as well. If not, then going to have head spacing problems. Same goes for hammers, since Armalite spec uses thinner hammers, and it will wedge if you have a DPMS spec width hammer with Armalite spec carrier, going to cause problems as well. |
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Posted By PlaymoreMinds:
'Twas not the <cough> sweet and innocent <cough> PlaymoreMinds... <---skips away in frilly skirts to Candyland, leaving gutters and snorkels FAR behind. |
[#16]
Originally Posted By QtrHorse: Are you using this buffer? If yes, is it the AR15 length or AR10 length (5.9in vs 5.2in)? https://www.ar15.com/media/mediaFiles/278288/IMG_2754-3127092.jpg View Quote My buffer weight is what you have pictured it is 5.2” |
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[#17]
Originally Posted By Dano523: And on PPS butt stock, are you using a shorter A1 bolt, and not the longer A2 that would be protruding into the receiver extension void area? As for bolt not moving at all, either gas leak, or gas blockage. Hence some gas blocks are set up to use forearm clips, some are not, so don't just slam the gas block all the way back against the shoulder, until you messure distance from shoulder to gas port, then same on gas block, to see if it needs to be gapped off the barrel shoulder of not to align with the barrel gas port. As for gas leakage, CLP around back of carrier key, hold the bolt in wards, then pressurize the front of the key to make sure it not leaking against the top of the carrier surface. Same for gas block to barrel and tube, and pressurize gas tube from withing the receiver. Last one, there is dmps/stoner spec for 308, then armalite in 308, and the two are not the same. So figure out what upper parts in play, and make sure that barrel is same spec as well. If not, then going to have head spacing problems. Same goes for hammers, since Armalite spec uses thinner hammers, and it will wedge if you have a DPMS spec width hammer with Armalite spec carrier, going to cause problems as well. View Quote The bolt moves just fine I’m not sure who started that issue. I’m not sure what you mean by A1 and A2 bolt length? The Toolcraft BCG that I have is listed for AR10/LR308/6.5 Creedmoore. |
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[#18]
I can’t tell you how many times I have seen posted over the years your problem in both ARs and LRs. The issue has often been caused by the gas tube being put in upside down or the gas tube pin put in front of the gas tube instead of through it. Easy mistake to make and correct, and it cost nothing to correct.
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Join the N.R.A.
Beware speaking with a sharp tongue as you are apt to cut your own throat. My name is John Wick, you killed my puppy, prepare to die. |
[Last Edit: Homesteader375]
[#19]
Originally Posted By 50dan: The bolt moves just fine I’m not sure who started that issue. I’m not sure what you mean by A1 and A2 bolt length? The Toolcraft BCG that I have is listed for AR10/LR308/6.5 Creedmoore. View Quote I believe Dano is referencing the bolt holding your prs stock to your receiver extension should be the short bolt native to an A1 stock. An A2 stock would have required a longer bolt and a spacer. If the longer bolt were used without the spacer, the buffer might hit the end of the bolt protruding into the receiver extension, preventing complete cycling. Not the BCG but the threaded bolt in the stock. |
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