I get it figured out you may hear a shriek of 'EUREKA!' on the winds. Followed by a post on it.
In the meantime, I suggest reading this: "Men only want one thing"
In the meantime, I suggest reading this: "Men only want one thing"
Addition: information added in comments, as some of you have far more experience than I
23 comments:
I am very familiar with AR's. I toted an M16 for 20 years and have built/own several. I wish you had described your problem as then I might have been able to help you.
Graduated U.S. Army Small Arm Repair School at Aberdeen Proving Grounds in 1974. Been building, shooting, handloading for AR's pretty much ever since. Be glad to offer my 2 cents. Full caveat, could be worth exactly that. Also if you haven't already, you might poke around here--
https://www.youtube.com/@SchooloftheAmericanRifle
Well,,what is the problem? I found a brand new gas tube that wasn't drilled. It was a single shot.
I would check with The School Of The American Rifle. SOTAR. That guy is sharp.
Maybe you could run the issue by BigCountry over at BigCountyExpat.com and see if he has any ideas. He's a bit of a gunsmith and did armory work when he was .Mil.
So what is the problem?
Sleeping with your rifle next to you or buying it fancy new attachments does not make it weird.
-lg
Ok, guys, here it is:
It's a AR308, DPMS upper & lower, 20" barrel, rifle-length gas system, Superlative gas block. Did some tweaking and it works fine. Until you put a suppressor on. Then it starts either leaving the last case on top of the magazine, or jamming with a case in the receiver, mouth to the rear, sometimes a smokestack.
I've checked the extractor and springs, the ejector, messed with the gas adjustments, no change. About the only thing I haven't done is change the gas tube. Any ideas?
I've seen that one, and not the same. Dammit.
https://www.youtube.com/watch?v=MlKFAnSMs_o
Read the comments too.
Bugger. Only other thing I can think of is the magazine you use. I know it sounds stupid and it shouldn't make a difference, but remember the Partisan trigger you posted about? They ran 10 different magazines with it to show it didn't misfire, so maybe?
-lg
My guess: overpresure in gas system. OLD FAL guys remember the adjustable gas system they had to account for such things. If you had some scrap gas tube, you could try crimping it just a little to get less gas, but still enough to cycle.
--generic
Does the gas adjustment change the bleed off, the pressure to the tube or both? The length of the gas tube determines the dwell time and that doesn't change. It sounds like over pressure. A rifle length tube has a shorter dwell but a higher initial pressure. A suppressor will increase both the pressure spike and the dwell. The bolt is getting a hard, sharp bang. Heavier bolt? Heavier buffer? Gas tube restrictor?
Is the suppressor for a different diameter bullet?
The suppressor is affecting the gas pressure which affects bolt operation. I can't tell you how to fix it. Maybe an adjustable gas block or a piston setup. Keep us posted.
Sounds over gassed. Heavier buffer. Without the can, what's the gas block setting you got to after tweaking?
Heavier buffer and spring to slow cycle time. Adjust gas block down. Dwell time is the time the gas system is charged, ie the time the bullet passes the gas hole (charged) until it leaves the barrel (discharged) and cannot be adjusted without changing the barrel and gas’s tube length and location. Pressure is adjusted with the gas block. Cycle slowed with heavier buffer and/or spring. Look at the threads on your lower receiver. AR10s bolts will slam into the threads when over gassed.
From what you've said, you can't dial it out through adjustment of the gas block. Does it happen with all magazines? If so, maybe a heavier buffer(?)
Maybe something like this:
https://www.opticsplanet.com/griffin-armament-ar-sob-suppressor-optimized-buffer.html
From here:
https://www.opticsplanet.com/ar-15-buffer-assemblies.html?_iv_parent-gun-model=ar-10
Big Country Expat!
I don't want to go to a heavier buffer, because I found out what that would cost.
Changing barrel because of port size, same.
The Superlative gas block has a total of 48 clicks of adjustment: from closed, open 18 gives you a fully open port, max pressure. With it open an additional 8 clicks it functions perfectly without the can. I've tried it with up to 46 clicks of bleed-off mode with the suppressor. I think I'm going to open it to max, and try it again now that it's all been fired and settled in a bit.
And I'll keep reading.
Seen ar-10's and SR25 do the same thing. Over gassed so the rifle is cycling too fast. As many other here have said.
The only thing field expedient solution I've seen fix it is mass and resistance. Heavy buffer and stiffer spring. Unless you get lucky it is the most cost effective in my experience. That and your adjustable block, if done right will get great cycling both suppressed and unsuppressed.
On a bench maybe barrel with smaller gas port or restricted gas tube. But then you're messing with the formula that works unsuppressed. A gamble or lots of potential tinkering (time and parts).
Forgot to add. Where do you throw brass? Both suppressed and not. That will give the best detail on how much adjustment you need. Likely cycling unsurpassed at the edge of too fast. And while pricey, buffer and springs a non permanent alteration as well.
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