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First time out with my Grendel I loaded one round, shot, and kept opening gas block until bolt carrier locks back on empty magazine. Then I opened it another 180 degrees.
Today was the second time shooting it. Loaded mags with 4 or 5 rounds, ejected rounds had dented case mouths and the carrier wouldn't lock open on empty magazine every time. About every other time the carrier would eject the round but would slide forward and close on an empty chamber. When I pulled the charging handle to the rear it would lock back.
I assume I need to open the gas block more?
How do you know when you have it right? Can you open it too much and how can you tell?
Rob
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You could have to much gas. Did the directions specify to open a half more turn after acheiving bolt lock back? From what I have read on this site, I haven't got mine together yet, to much gas can mimic not enough because the BCG is moving faster than the Mag can respond. The dented case maouths is fairly common and can usuallty be fixed with some cushion on the brass deflector. The soft(loop) side of adhesive velcro tape seems to be the preferred choice.
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04-11-2014, 10:09 AM
(This post was last modified: 04-11-2014, 10:13 AM by Drifter.)
You might have some carbon buildup internally, and may need to open the gas block another click or two.
Also, different ammo will operate the system differently. If you tune the weapon to run smoothly with a slow-burning powder, you will likely experience short-stroking with faster-burning propellents.
Changing the BCG, buffer, and / or buffer spring might also necessitate re-tuning the system for proper function.
What is your barrel length and gas system length, and what ammo are you using?
Drifter
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You may have to allow 0.025" between the shoulder & the gas block so the gas port in the barrel lines up to the gas block correctly.
if it wont stay open on empty, sometimes its too much gas, how is the ejection? really far away?
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+1 on over gassing. I have the Syrac adj block and did not open an extra 180° and have had no problems.
Posts: 105
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20" barrel with rifle length gas system with standard rifle buffer shooting factory Hornday 123 A-max. If I remember right the instructions didn't say much. I youtube'd a video on adjusting gas block. It was a different manufacture also. Ejected cases aren't very far away, I'd say the distance is consistent with 223rem cases. They ejected to the 3 to 4 o'clock position.
I'll turn it down a half turn. I really don't want to have to re-position the gas block again.
