HOUSTON I have a problem.

[kalielkslayer]

Maybe this should be in the gunsmith section, if so, please move it.

I recently got a PSA upper kit for 5.56. After I put it together, the first time i shot it, by the 5th round, I felt it was over gassed. I had one case stuck in the bore but the ejector had ripped the rim, my cases were ejecting at 1230-1300. These was with 5.56 ammo. I shot a few .223 through it and although it functioned, ejections were still close to 1300.

I considered the options and decided on an adjustable gas block, and got the Odin so I could count clicks instead of turns.

I should note that I have a full length “free floating” hand guard so I have to remove it to adjust the gas block.

Yesterday, I started at one click fired a round, bolt didn’t lock back. I continued one click at a time until I got it to lock back at 6 clicks. Kool, now see if it’ll feed. 3 rounds, fed flawlessly and locked back. Replaced the arm guard and fired again. Didn’t pick up the 3rd round. It was getting late so today I removed the hand guard adjusted 1 more click, perfection. And ejected cases are between 3:30 and 4:30.

As I was testing for function, I was adjusting the red dot too. You can see from the photos each group climbing up. I wasn’t really focused on accuracy but I was trying to kill 2 birds with one stone.

Then I put the arm guard back on and 3” right. Then I remembered the night before my 3 shots with the hand guard on were right also.

This is where I need help. Apparently the hand guard is applying pressure on the left side of the barrel? The hand guard has a set screw on top that kind of locks the hand guard to the receiver, a set screw on the right side that may screw to the other side of the hand guard, or the barrel? And 3 hex bolts that do tighten the hand guard around the barrel.

What are my options? Loosen the side set screw? Maybe just tighten it enough so I can feel a little tension and use locktite on it? Make a scope adjustment but I feel I’ll continually go right so even if it on at 100 yards, it’ll be right at 200. Get a higher quality hand guard?

I don’t expect this gun to shoot 1 hole groups as a 2 MOA red dot sits on it.

I attached the target photos so you can see what I’m talking about.

 

[Robert]

If your hand guard is touching the barrel something is bent or misaligned.

 

[Citron]

Is this a low profile handguard? Some of them can be small enough ID that they will contact the gas block. Especially with the adjustable gas block, since they are usually bigger than low profile gas blocks.

 

[kalielkslayer]

Yes it’s low profile. When I slide the Hand guard on, it touches the gas block. I kind of have to push it slightly away to get it from touching. But when it’s seated and bolted, the edge of the gas block is in a “web” of the hand guard where it doesn’t appear to be touching.

I’ll inspect it closer tomorrow. The metal is shiny, bluing gone, on the very corner of the gas block. I thought that was from nicking it sliding it on. Maybe it’s touching. If so, problem solved.

Thanks for the input.

 

[Robert]

I'd make sure the mounting screws for the handguard are equally torqued. If it is still touching, try a different handguard. Applying any pressure to the barrel is going to cause problems.

 

[DMW1116]

My PSA 16” upper hand guard was touching the gas block. I took it to them and they loosened it and turned it. It was still touching just a bit so I loosened it and turned it when I got it home. The top of the gas block where the tube goes was just barely touching the side of the groove in the hand guard. It wasn’t really causing problems but it was just annoying. I think the newer generation of uppers are dimpled so turning the gas block a degree or two might not work.

 

[H&Hhunter]

I had a spike tactical brought to me with a caddyswompis hand guard. The barrel nut was cross threaded and at an angle, whoever did that destroyed the upper. The threads on the upper were trashed.

 

[kalielkslayer]

My PSA 16” upper hand guard was touching the gas block. I took it to them and they loosened it and turned it. It was still touching just a bit so I loosened it and turned it when I got it home. The top of the gas block where the tube goes was just barely touching the side of the groove in the hand guard. It wasn’t really causing problems but it was just annoying. I think the newer generation of uppers are dimpled so turning the gas block a degree or two might not work.

If it was touching and didn’t impact accuracy, I wouldn’t mess with this. But it’s terrible.

 

[ColoradoMinuteMan]

The short of this is that something is geometrically out of alignment. IMHO, the best way to approach this is starting to examine where the geometry is off. Is it the barrel in alignment with the upper; is the gas block aligned to the barrel; is the handgaurd aligned to the upper; is the barrel nut aligned to the upper; is the handgaurd aligned to the barrel nut? Until you understand what is out of alignment this will be most a lot of guessing on how to fix the issue.

 

[kalielkslayer]

So if it shoots well with the hand guard off, but not on, doesn’t that eliminate the barrel and barrel nut?

 

[greyling22]

So if it shoots well with the hand guard off, but not on, doesn’t that eliminate the barrel and barrel nut?

I would think so.

 

[d2wing]

If it is free float it must have enough clearance to not touch as the barrel vibrates while shooting.

 

[adcoch1]

Time to check the alignment of the gas block, then decide if it's a new handguard or grinding the gas block down to fit. My odinworks adjustable BARELY fits under my fortis knight rail. But it doesn't touch. But any misalignment and it would. Do a little research on which handguard will clear the gas block, maybe you can find one that'll work better.

 

[kalielkslayer]

Time to check the alignment of the gas block, then decide if it's a new handguard or grinding the gas block down to fit. My odinworks adjustable BARELY fits under my fortis knight rail. But it doesn't touch. But any misalignment and it would. Do a little research on which handguard will clear the gas block, maybe you can find one that'll work better.

I haven’t messed with it since I started the post. Monday I will. I have no doubt it’s touching the gas block on the left side thus the point of impact going right.

Even thought cutting the hand guard is an option.

when we took it apart to put the adjustable gas block on, I’m not 100 percent sure it’s perfectly straight. I’ll verify that first.

 

[horsemen61]

I haven’t messed with it since I started the post. Monday I will. I have no doubt it’s touching the gas block on the left side thus the point of impact going right.

Even thought cutting the hand guard is an option.

when we took it apart to put the adjustable gas block on, I’m not 100 percent sure it’s perfectly straight. I’ll verify that first.

Any news?