AR Barrel Nut Loose

[Misery Loves Shotguns]

We were shooting my wife's AR today and I noticed that the barrel seems to be loose. The upper itself isn't the problem because I have a rubber wedge that keep it's pretty tight. When I grab the A2 sight post, I can wiggle the barrel back and forth a little bit. Not much but enough. Anyway, she can usually targets standing at 50 yards with no problem but we couldn't hit a damn thing with it today. Switched to my rifle and we both shot the way we're used to. We bought her rifle used so maybe the guy built the upper himself and didn't torque it down properly? Anyway, if anyone local (I live in Crafton, shoot at PMSC) has the necessary tools to fix this for us or would let me borrow them, I can either pay you or give you some ammo or I could just buy one if someone can recommend one. I ordered a barrel wrench today, have the vise block and a vise. I just need the torque wrench.

[SgtRecon]

Im sure Ill get flamed for this ...but a torque wrench is not needed, lightly oil the threads and snug it down good, The few times I've tried to use a torque wrench, the barrel nut never lined up for the gas tube at specified torque, needing to be loosened or tightened a bit to get the tube to align, thus negating the torque. Ive developed a "calibrated forearm" your milage may vary

[dkf]

Not all that uncommon for a "builder" to not torque the barrel nut at all or do it wrong. The specified torque range is 30-80ft lbs. If you can't get the barrel nut clocked properly in that range then you got issues. Though me personally I'd rather go a tad over 80 than be on the low end. I'd help you out tightening it up but I'm on the wrong side of the state from you. It is likely the barrel nut is just loose but I'd check to make sure the barrel extension is tight to the barrel and the pin is solid.

[danhr]

We were shooting my wife's AR today and I noticed that the barrel seems to be loose. The upper itself isn't the problem because I have a rubber wedge that keep it's pretty tight. When I grab the A2 sight post, I can wiggle the barrel back and forth a little bit. Not much but enough. Anyway, she can usually targets standing at 50 yards with no problem but we couldn't hit a damn thing with it today. Switched to my rifle and we both shot the way we're used to. We bought her rifle used so maybe the guy built the upper himself and didn't torque it down properly? Anyway, if anyone local (I live in Crafton, shoot at PMSC) has the necessary tools to fix this for us or would let me borrow them, I can either pay you or give you some ammo or I could just buy one if someone can recommend one. I ordered a barrel wrench today, have the vise block and a vise. I just need the torque wrench.

I live in Ford City and shoot at North buffalo sportsman's club and Ford City sportsmans club. I have a torque wrench, armors wrench, blue loctite, vise block, and a big ole vice.

[Gunsnwater]

Harbor freight for the torque wrench. Put the torque wrench in the square hole 90 degrees. That puts the center line of torque at the center of nut rotation. In other words, you didn't make the torque wrench longer. Together it will look like an L. Start checking gas tube alignment at 30. If for some reason it's not right by 80 use a ratchet or breaker bar to back the nut off all the way. Torque wrenches are a measuring tool. Don't use a torque wrench to break a nut free. Every time you reseat the nut it will go on a tiny bit farther. Don't back off the nut to align the tube. You won't have proper torque. It's not hard to do things correctly, you just need to know the technique. Some very good builders will true the face of the upper so the extension on the barrel has full contact when seated.

[bjmac]

Harbor freight for the torque wrench. Put the torque wrench in the square hole 90 degrees. That puts the center line of torque at the center of nut rotation. In other words, you didn't make the torque wrench longer. Together it will look like an L. Start checking gas tube alignment at 30. If for some reason it's not right by 80 use a ratchet or breaker bar to back the nut off all the way. Torque wrenches are a measuring tool. Don't use a torque wrench to break a nut free. Every time you reseat the nut it will go on a tiny bit farther. Don't back off the nut to align the tube. You won't have proper torque. It's not hard to do things correctly, you just need to know the technique. Some very good builders will true the face of the upper so the extension on the barrel has full contact when seated.

I'm going to disagree with the *90 offset as far as the torque spec is concerned. Ever notice all nut wrenches locate the "pivot" the same distance from nut center?

To the op, be positive that the barrel is actually moving. I would assume you would show pressure signs if the barrel is in fact that loose. Is this a scoped rifle or open sights? I ask only because it is fully possible that the fs is loose and you're most likely using open sights with an a2 fsb. An accuwedge can still allow movement between the upper and lower.

[bjmac]

We were shooting my wife's AR today and I noticed that the barrel seems to be loose. The upper itself isn't the problem because I have a rubber wedge that keep it's pretty tight. When I grab the A2 sight post, I can wiggle the barrel back and forth a little bit. Not much but enough. Anyway, she can usually targets standing at 50 yards with no problem but we couldn't hit a damn thing with it today. Switched to my rifle and we both shot the way we're used to. We bought her rifle used so maybe the guy built the upper himself and didn't torque it down properly? Anyway, if anyone local (I live in Crafton, shoot at PMSC) has the necessary tools to fix this for us or would let me borrow them, I can either pay you or give you some ammo or I could just buy one if someone can recommend one. I ordered a barrel wrench today, have the vise block and a vise. I just need the torque wrench.

I need some more info. See my above post.

[polishprince]

Whenever I've put an upper together,I always brush the barrel nut threads with the threadlocker that needs to be heated with a torch to come loose,like a lot of the big companies do. Usually green in color. A defensive arm that might shake itself loose is not something to gamble on.

[danhr]

Whenever I've put an upper together,I always brush the barrel nut threads with the threadlocker that needs to be heated with a torch to come loose,like a lot of the big companies do. Usually green in color. A defensive arm that might shake itself loose is not something to gamble on.

green locktite is low strength, and breaks apart at 300*F. You can get your barrel to 300*F in 30 rounds.

I usually go with blue myself.... that's just me though.

[Jhaydeno]

Whenever I've put an upper together,I always brush the barrel nut threads with the threadlocker that needs to be heated with a torch to come loose,like a lot of the big companies do. Usually green in color. A defensive arm that might shake itself loose is not something to gamble on.

green locktite is low strength, and breaks apart at 300*F. You can get your barrel to 300*F in 30 rounds.

I usually go with blue myself.... that's just me though.

Why go with either? The barrel nut can't back itself off if the gas tube is in place, and a little bit of back off pressure isn't going to shear or pinch a gas tube.