Am I tightening my barrel right

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[ARCHIVED THREAD] - Am I tightening my barrel right

Posted: 10/27/2006 10:49:35 PM EDT

I put a little bit of grease on the receiver threads and screw on the nut.I use the wrench until the nut is snug and stops it lines up with a tooth a half turn from clearing the opening to insert the gas tube..I do this 3 times then use a bit of force for the final half turn to line up the opening with the receiver hole so the tube goes right in.Is this good to do..I use a regular barrel wrench for this.Also can a barrel nut that hasnt been tightened enough but is not loose effect the barrels acuracy when fired?thanks ....Dave

Posted: 10/28/2006 12:02:50 AM EDT

[#1]

Have you read the tacked threads in the "bulid it yourself" forum in the AR-15 section?

If you have an idea what 31 ft/lbs of torque is then you have an idea what the minimum is. If you are 1/2 slot off aligned when snugged then the next hole lined up is usually enough. If it is real easy to achieve the next alignment slot then you should try to achieve the next slot. 80 ft/lbs (max torque) is quite a bit of force and you don't want to exceed it. I can't think of a good example to give you for min/max torques. Just remember to work it back and forth to get to the slot you intend to use.

Posted: 10/28/2006 7:21:29 AM EDT

[#2]

I can get it to the next slot..it takes a bit of force to get that last littlr bit.On another carbine I have that I installed its a tack driver.The factory Bushmaster upper that I did last night it wasnt on too tight and was real easy to turn off and its 10 years old..switching to a flat top..thanks for the info

and thats what I figured the first slot that lined up was snug but it still felt I could go one more and it stopped half way..then It took a little force to get it to line up but it did..thanks again...Dave

Posted: 10/28/2006 8:17:31 AM EDT

[#3]

you're good to go

Posted: 10/28/2006 9:26:34 AM EDT

[#4]

I hand snug first and then wrench it over to align the hole for the gas tube; sometimes that is half a hole, sometimes it is a full hole, it all depends.
~snap~

Posted: 10/28/2006 3:45:25 PM EDT

[#5]

I just got my CMT upper from PK firearms today..are they nice uppers..fit and finish is excellent.It tourqued perfectly to an open hole the first try..I lossened and tightened 2 more times and it lined up perfect.As I came to a point where it wouldnt turn it was lined right up..what a great upper cant wait to get my removable handle from them on tuesday and then im gonna get a ARMS#38 swan sleeve and put my aimpoint on that set up.

Posted: 10/28/2006 4:32:32 PM EDT

[#6]

I've installed five barrels, on a few they didnt lined up,had to loosen in order for it to lined up properly.

Never have had any issues with the ones I'd installed.

TG

Posted: 10/28/2006 5:57:21 PM EDT

[#7]

I also like to tighten the nut three times. Tighten and the loosen, repeat, then tighten a final time. I never saw any difference in accuracy in how much tork is applied to the barrel nut. As long as you are above 35ft/lb just line up to the next notch.

Posted: 10/28/2006 6:50:43 PM EDT

[#8]

You guys covered it real well.

It is most important to tighten and back off the barrel nut a few times to "chase" the threads. This removes excess anodizing and allows you to get a proper torque on the barrel nut to receiver fit.

I prefer to build my uppers tight, but that is just me.

Denny

Posted: 10/28/2006 8:19:48 PM EDT

[#9]

Quoted:
on a few they didnt lined up,had to loosen in order for it to lined up properly.

Never loosen the nut to gain alignment unless the amount you are loosening will still alllow you to be over about 30ft-lbs of torque.
The way to do it is to break the nut loose and re-attempt alignment.
In other words, set the torque wrench to 30ft-lbs.
Snug the nut until it clicks.
Then set the wrench to 80lbs,
Now comtinue to snug the nut until it aligns.
If the wrench clicks, you are too tight.
Re-seat the nut a few more times to mate the threads better.
This will give you a little more travel at the same torque setting.

[ARCHIVED THREAD] - Am I tightening my barrel right

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