Canted low-profile gas block

[TripleDigitRide]

Is it canted too far? I haven't had a chance to shoot it, so I thought I'd get some opinions before I do.

 

[Lumber_Jack]

Yes

Two things.

1) are the gas ports lined up. If not it might not cycle

2) the gas tube will be at an angle (albeit small) and will not be square with the gas key on the bolt. This can cause uneven wear.

Is there a reason it's not 90 degrees from horizontal? I mark the gas ports on the barrel with a pencil and then the same on the block, then line up the marks Edited January 27, 2013 by Lumber_Jack

[TMF]

Depends on where the gas port is coming out of the barrel. I have a hard time believing the gas port was that misaligned when they drilled it, but who knows. You'll know as soon as you shoot it if it's lined up or not. If it ain't your gun won't cycle.

Did you just buy this or have someone put it on for you? Edited January 27, 2013 by TMF

[Lumber_Jack]

Ps I'm no expert. If it runs, you may never see any problems.

[TripleDigitRide]

This complete upper is brand new and came to me like this. I did some trading with a member here on TGO. I've never had one apart, but it looks like I may have to learn.

[TMF]

[quote name="TripleDigitRide" post="897419" timestamp="1359309224"]This complete upper is brand new and came to me like this. I did some trading with a member here on TGO. I've never had one apart, but it looks like I may have to learn.[/quote] Well I don't want to talk smack about another member, but it looks like they use a metallic object to smack that gas block in place since it's so scratched up. They coulda just used a small piece of wood or something if they were that hard up for proper tools. Based on that observation I'm gonna go out on a limb and assume they did this themselves and did a poor job.... just basing that on the scratches. So I can assume the cant is not correct and either partially or completely obscures the gas port. You can take it shooting and see if it works. If it does great. I can't speak to whether or not the uneven wear will be a serious problem; that's a Dolomite question there. If it doesn't cycle, which I suspect is the case, you're gonna have to re-pin it. I assume it is held to the barrel with one or two roll pins. This is gonna be tricky since the place where you'll need to have the roll pins set will be the same spot on the barrel where it's already drill, just off canter. I'd say that's gunsmith territory to make sure it's done right so it won't wiggle out of place due to the previous drilling. Paging Dolomite...

[Lumber_Jack]

This complete upper is brand new and came to me like this. I did some trading with a member here on TGO. I've never had one apart, but it looks like I may have to learn.

Well I'll say this. It's not normal. There may be enough gas getting through the ports to cycle, but it may not be optimal. Especially cosidering the gas key wear I mentioned above. Fixing this should be simple but will take removing the rail and flash hider.

I'd take the gas block all the way off to check the port alignment

[Lumber_Jack]

Well I don't want to talk smack about another member, but it looks like they use a metallic object to smack that gas block in place since it's so scratched up. They coulda just used a small piece of wood or something if they were that hard up for proper tools.Based on that observation I'm gonna go out on a limb and assume they did this themselves and did a poor job.... just basing that on the scratches. So I can assume the cant is not correct and either partially or completely obscures the gas port. You can take it shooting and see if it works. If it does great. I can't speak to whether or not the uneven wear will be a serious problem; that's a Dolomite question there.If it doesn't cycle, which I suspect is the case, you're gonna have to re-pin it. I assume it is held to the barrel with one or two roll pins. This is gonna be tricky since the place where you'll need to have the roll pins set will be the same spot on the barrel where it's already drill, just off canter. I'd say that's gunsmith territory to make sure it's done right so it won't wiggle out of place due to the previous drilling.Paging Dolomite...

These low pro gas blocks often use set screws to hold them in place. If that's the case it's an easy fix as long as you have a vise block and some wrenches.

[Lumber_Jack]

With everything said. It this is a set screw gas block. You may be able to loosen, straighten and retighten the gas block with minimal effort. May still have to remove the rail

[TMF]

[quote name="Lumber_Jack" post="897429" timestamp="1359310121"] These low pro gas blocks often use set screws to hold them in place. If that's the case it's an easy fix as long as you have a vise block and some wrenches.[/quote] I hope that is the case. I haven't done a low pro build in 7 years, but the one I did the gas block had a set screw to hold it in place but you still had to drill for a roll pin.

[TMF]

[quote name="Lumber_Jack" post="897432" timestamp="1359310286"]With everything said. It this is a set screw gas block. You may be able to loosen, straighten and retighten the gas block with minimal effort. May still have to remove the rail[/quote] Yeah, I second this TDR. Get that rail off and see what you're working with.

[TripleDigitRide]

According to the person I got it from, he got it from a local shop. The scratches aren't nearly as noticeable as they appear in the photo.

I'll take it apart and see what I can figure out.

[mikegideon]

I have the same situation on my Blackout rifle. It's a Daniel Defense block under a Daniel Defense Lite Rail. The barrel is an AR Stoner (Shaw?). The barrel has an indentation opposite the gas port, and I aligned the block to that under a magnifier. No way it's THAT misaligned, since the rifle cycles all my loads with a carbine gas system and an M16 BCG. It's also driving the stiff hammer springs that come with a Geissele trigger.

 

I will take the rifle down and make use of the slop in the gas block hole just to increase the gap between the block and the rail. With that said, I believe the root of the problem is the Stoner barrel,

[56FordGuy]

I wonder if the entire barrel is off a bit. If the gap in the receiver were a bit too wide, or the pin on the barrel a bit too small, the gas block could theoretically be installed on the barrel properly and the whole thing is out of whack. Edited January 27, 2013 by 56FordGuy

[mikegideon]

I wonder if the entire barrel is off a bit. If the gap in the receiver were a bit too wide, or the pin on the barrel a bit too small, the gas block could theoretically be installed on the barrel properly and the whole thing is out of whack.

 

My pin in the upper receiver was tight. The extension and/or the gas port is just canted a little. I'll use what little slop is available to fix mine. My feed ramps (M4) appear to be aligned pretty well

[TripleDigitRide]

I wonder if the entire barrel is off a bit. If the gap in the receiver were a bit too wide, or the pin on the barrel a bit too small, the gas block could theoretically be installed on the barrel properly and the whole thing is out of whack.

Yeah, that's beyond my current knowledge of ARs. Looks like I'll be learning in short order.

[Lumber_Jack]

Yeah unless the pin in the barrel extension is extremely too small for the slot in the upper receiver, I can't see how the barrel could be misaligned.

As Mike stated I have heard several people complain the gas ports on their AR Stoner barrels was not at 90 degrees from horizontal.

Remember, just because it was assembled at a "shop" doesn't mean it's right

[mikegideon]

If the pin is off, the feed ramps will be misaligned as well.

[56FordGuy]

Yeah, that's beyond my current knowledge of ARs. Looks like I'll be learning in short order.

 

It's not 'right' now. Taking it apart can't hurt!  :rofl:

[TripleDigitRide]

Thanks to 56FordGuy, the issue is resolved. It was just a matter of removing a couple set screws and adjusting the gas block. We didn't try before fixing it, but it functioned perfectly after he was done.

Thank you very much for your help and wisdom.

[Dolomite_supafly]

I bought a "new" barrel that had the port at 1 o'clock with the alignment pin at 12 o'clock. It does happen and doesn't affect function as long as the ports are aligned. Cosmetically it would drive me nuts. But as Lumber Jack said it can cause the gas tube to no be aligned properly and this will wear out the end of the gas tube. When that happens the gun will quit cycling.

 

I suspect had you not fixed it the gun would have not cycled.

 

Dolomite