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I have a new build with an 18 WC Recon Tactical barrel. I used an Odin AGB. As I was assembling I saw an insert with the barrel that said it wasnt recommended to use AGBs with the barrel. But if you did, start with it wide open. So I shot it for the first Time today and did what Odin said not Wilson and started with the block closed and worked my way up until it stayed open on a empty mag. Well it never did. I opened it way up and it eventually ejected shells but it never stayed open on empty mag or chambered second shell. I assume wide open is getting the screw so far out that the set screw wont fit back in. Thats where it is anyway. So first, is it just foolish to think the Odin GB will work with the WC barrel and should I buy a WC block ? Or am I still not adjusting this right? Its my first build so I dont know anything more than Ive read here and elsewhere.
thx!
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I suggest you measure your gas port. I suspect Wilson Combat recommends against an AGB because of their gas port size. You didnt mention whether this barrel is mid length gas system or rifle length gas system. If using a suppressor many forum members prefer rifle length gas system on 18 barrels.
Mid length gas system 18 barrels seem to have more dwell time issues with 18 barrels compared to rifle length gas system on 18 barrels.
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It is a rifle gas system. Sorry for the stupid question, but once I measure it then what?
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I think there is a gas-port sizing guide for the Grendel on here, use the search function.
If your port is too small then the rifle won't cycle correctly. But an adjustable gas block, wide open, shouldl behave the same as a plain gas block. The Key is gas port size.
Sometimes a gas block that is installed back flush against the journal stop, means the GB hole is not lined up with the barrel port, but that may not mean anything as the GB hole is typically wider than the barrel port-hole anyway... but front/rear alignment of the GB is a good thing to ensure you're ok in.
"Down the floor, out the door, Go Brandon Go!!!!!"
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05-24-2020, 03:46 AM
(This post was last modified: 05-24-2020, 03:52 AM by VASCAR2.)
The info I have for a 18 6.5 Grendel with rifle length gas port should be .094. If the gas port is the correct size Id ensure the AGB screw was moving and not stripped. If you pull the gas block there will probably be carbon showing whether the gas block was centered over the gas port.
If the gas port is to small you can contact Wilson Combat or drill out the gas port yourself. Ballistic Advantage assumes most user will have suppressors and uses a small gas port on their shorter barrel lengths. I dont remember any prior issues with Wilson Combat gas port sizes but that doesnt mean your gas port is the appropriate size.
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So which Odin gas block do you have, the tuneable or the adjustable one with the front knob for settings? If the tuneable one, you do realize that there are two set screws in the front port?
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I have the tuneable one. I know that the hole closest to the barrel has a stop screw thats I totally removed and then adjusted just the adjusting screw. I know its moving because the gun didnt eject when gas was off, then I could get it to eject when I opened it. Is there another screw Im missing?
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Ive got some pics to post but I cant figure out how. When I hit go to advanced I dont see a manage attachments link. This is from my phone. What am I missing? I want to post pics of the gas marks to see if you guys think i have alignment or leaking issues.
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Based on the carbon ring on the barrel it looks like the gas block needs to be moved forward towards the muzzle end. I can't tell exactly from the picture if the gas port is being occluded by the block but it seems so to me.
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Without a bore scope or shooting it, is there a trick for confirming alignment ? Everything I read says confirm alignment) but nothing tells a noobie like me HOW!
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05-24-2020, 06:19 PM
(This post was last modified: 05-24-2020, 06:21 PM by Lastrites.)
That gas block has a line engraved into it underneath the gas tube to add in alignment, so take a pencil and strike a line bisecting the gas port over the shoulder. Take gb and remove the set screw underneath the blocks gas port, slide it on upside down on the barrel and line up that set screw hole to the gb port and take note of how far off the barrel shoulder that perfect alignment takes place. Rotate gb and align the pencil mark to the engraved mark with the proper gap from the shoulder and tighten.
It sure looks like you have a decent amount of gas leaking from your block to the barrel and the gas tube and that is likely an issue. Odin has good customer service you may want to reach out to them and discuss it with them and sending them pictures would be good, if you can measure the gb journal and the opening of the gb that may shed some light. My tunable block didn't spue out gas as your pictures show. Some guys use loc-tite to bed their blocks and gas tubes but one needs to be careful doing that as you don't want it to get in your port.
eta; be careful installing the locking long setscrew for adjusting the gas as I've heard others mentioned they noticed when they screwed it down to lock the inner screw that it actually turned the inner screw as well changing the gas setting.
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Ok so progress! Lastrites, I noticed what you noticed. So I looked more closely where the block was installed. It looked like I didnt butt it up righ on the shoulder if the barrel. So I actually moved it back towards the chamber and really tightened it up. I also lubed the spring and the bolt again but ultimately I think repositioning the gas block was the issue. I started wide open and kept closing it up 2-3 turns at a time and it still kept functioning cycling rounds and staying open on final round. So how closed to I set it? I eventually stopped because I was running out of ammo. And wanted to see if itll group at all. So far its not but I dont know if shooting and tweaking gas block affects POI. But I think my first AR build is actually running right well now so I cant focus on accuracy next!!
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Get yourself a box of wolf and see if it still functions, tune it till chokes then back it off a 1/2 to full turn so you have full function, when you think you have it right put a tiny drop of blue loc-tite on very end of the locking set screw near where the allen wrench attaches and gently screw it in till it stops. I added the loc-tite to mine when I had noticed the locking screw actually backed off due to recoil.
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For gas block alignment, I've used the Spaghetti trick for my last few builds. It's pretty hard to mess up.
Put a piece of spaghetti in your gas port and break it off flush with the barrel shoulder. Slide the gas block on, with the port up. Once you think you've got your port aligned, roll the barrel over, allowing the spaghetti to slide into the gas block's hole. You should wiggle the gas block in all directions to get a feel for where the hole centers are, then snug the set screws, pins, etc. Loktite one screw at a time, leaving the other tight enough to hold the block in place while you remove the other screw. Then put 15in lbs on the first, followed by the second. On my BCM gas blocks I tighten both screws to 25in lbs. After the screws are tight, roll the barrel back over port up, and use a cleaning rod to break the pasta off and push from the barrel. Easy as 1-2-3.
The pencil line was my old method, but that left me always feeling some apprehension about whether I had it forward of the shoulder enough, or whether this gas block was supposed to be touching the shoulder... etc.
Nothing kills the incentive of men faster than a healthy sense of entitlement. Nothing kills entitlement faster than a healthy sense of achievement.
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This is a great link on gas block alignment
http://www.65grendel.com/forum/showthrea...-gas-block
All my pasta was too big, so I used a toothpick.
