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Posted: 10/14/2018 7:21:51 PM EDT
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Just got a PSA 12” 6.5 Grendel upper, my first AR upper with an adjustable gas block.
I understand the process for tuning one, just don’t understand how to actually adjust it. Looks similar to an Odin block, with a large set screw in the front below the gas tube with a small screw on the side. So is the front screw to adjust the gas flow and the side screw is the lock screw? |
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The screw at front facing side of the gas block is the locking screw. The one on the side adjusts the gas. I emailed them this week to confirm. See pasted response below, this should really be on their website!
To adjust the gas system; 1. Make sure the firearm is unloaded. 2. Turn the barrel of the firearm so you can look down the barrel. 3. You should see a set screw. This is the lock screw that must be loosed to adjust the system. 4. Now that you've unlocked the gas block, look on the side of the gas block. You should see another screw. This is the screw that adjusts the gas going to the receiver. Adjust this screw. 5. Set lock screw, reload, fire. Check for malfunctions. 6. If the firearm does not cycle, repeat steps 1-5 until the system functions with your ammo type. 7. If this doesn't work or you have any further questions, please contact us again and we can move forward from there. Thank you for choosing Palmetto State Armory. |
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The screw at front facing side of the gas block is the locking screw. The one on the side adjusts the gas. I emailed them this week to confirm. See pasted response below, this should really be on their website!
To adjust the gas system; 1. Make sure the firearm is unloaded. 2. Turn the barrel of the firearm so you can look down the barrel. 3. You should see a set screw. This is the lock screw that must be loosed to adjust the system. 4. Now that you've unlocked the gas block, look on the side of the gas block. You should see another screw. This is the screw that adjusts the gas going to the receiver. Adjust this screw. 5. Set lock screw, reload, fire. Check for malfunctions. 6. If the firearm does not cycle, repeat steps 1-5 until the system functions with your ammo type. 7. If this doesn't work or you have any further questions, please contact us again and we can move forward from there. Thank you for choosing Palmetto State Armory. |
| I worked the small screw in and out several times and it seemed rather rough and I was worried I was going to strip the small hex screw. After doing that it went in fully and much farther than I originally had thought. It seemed I ended up around 2 full turns from closed. Overall no real issues and looking forward to seeing how accurate it will be. |
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I started fully open and I think it was about 3-3.5 full turns shooting Wolf steel case. I could have fine tuned it more but I wasn't looking to get to the fine edge of operations, I basically cranked it a half turn closed on every shot til my first FTF, then the next two shots were good so I got another 1 to 1.5 full turn in before it failed again so I did five shots with two failures and backed out a half turn and stayed there. No failures for the rest of the day (50-60 more rounds). I've heard running it dry is recommended but being a brand new upper with brand new mags I didn't want to create problems. I was also zeroing optics for the first time so starting fully open let me do all three simultaneously. I did notice a big change both in felt recoil and ejection once adjusted. I may put some Loctite on the adj. screw, supposed to help avoid carbon lockup. So I'd have to count the turns til it bottoms out from where it's set now, back it out, smear it with Loctite, then screw it all the way back in and back out the same # of turns. But I'm not running this suppressed so once the block is dialed in, I'm done. |
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Quoted:
I started fully open and I think it was about 3-3.5 full turns shooting Wolf steel case. I could have fine tuned it more but I wasn't looking to get to the fine edge of operations, I basically cranked it a half turn closed on every shot til my first FTF, then the next two shots were good so I got another 1 to 1.5 full turn in before it failed again so I did five shots with two failures and backed out a half turn and stayed there. No failures for the rest of the day (50-60 more rounds). I've heard running it dry is recommended but being a brand new upper with brand new mags I didn't want to create problems. I was also zeroing optics for the first time so starting fully open let me do all three simultaneously. I did notice a big change both in felt recoil and ejection once adjusted. I may put some Loctite on the adj. screw, supposed to help avoid carbon lockup. So I'd have to count the turns til it bottoms out from where it's set now, back it out, smear it with Loctite, then screw it all the way back in and back out the same # of turns. But I'm not running this suppressed so once the block is dialed in, I'm done. I tried adjusting the small silver screw on the side but it made no difference. But I was unable to screw it in all the way. |
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