NcPC Posted April 12, 2020 Report Share Posted April 12, 2020 Hey, I'm building my first 6.5 cm ar. Everything is in except my barrel. I was dry fitting my 17in utg pro handguard and based on the instructions I need to add the provided shims to get the holes aligned. Even with all 4 shims I have not achieved alignment. Anyone familiar with this? Thanks in advance. Quote Link to comment Share on other sites More sharing options...
sketch Posted April 12, 2020 Report Share Posted April 12, 2020 did you tourqe it down or hand tight? Quote Link to comment Share on other sites More sharing options...
Albroswift Posted April 12, 2020 Report Share Posted April 12, 2020 How would you know without the barrel? Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 12, 2020 Report Share Posted April 12, 2020 ^^^ Exactly. Quote Link to comment Share on other sites More sharing options...
NcPC Posted April 13, 2020 Author Report Share Posted April 13, 2020 It's a free float and screws to the upper Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 13, 2020 Report Share Posted April 13, 2020 (edited) 1 hour ago, NcPC said: It's a free float and screws to the upper That doesn't mean a single thing, until your barrel comes in, and you put the flange on that barrel right up against the upper, then screw that barrel nut down over the flange on that barrel. You are trying to figure this all out, without accounting for how thick that flange is, on your barrel, that you don't have yet. Edited April 13, 2020 by 98Z5V Quote Link to comment Share on other sites More sharing options...
NcPC Posted April 13, 2020 Author Report Share Posted April 13, 2020 Thanks for the feedback I did not know the barrel flange affected the depth of the barrel nut. Got about a week or two before my barrel gets here. I will update you guys and post the build if I'm able to complete it then. Quote Link to comment Share on other sites More sharing options...
Albroswift Posted April 13, 2020 Report Share Posted April 13, 2020 In the meantime why don't you describe your build? May have some good input for you. Quote Link to comment Share on other sites More sharing options...
NcPC Posted April 13, 2020 Author Report Share Posted April 13, 2020 Aero precision m5 upper and lower, aero precision bcg and gas block/tube, luth-ar a2 stock, mil spec lower parts kit and trigger. UTG pro 17in handguard, Hexmag magazine ( mag fits more snugly than I like) Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 15, 2020 Report Share Posted April 15, 2020 On 4/13/2020 at 4:05 AM, NcPC said: Thanks for the feedback I did not know the barrel flange affected the depth of the barrel nut. Got about a week or two before my barrel gets here. I will update you guys and post the build if I'm able to complete it then. It most definitely does, and you have to account for it - there's nothing that you can try to calculate, before you actually receive your own barrel, and install it. You can't figure out the timing of the barrel nut unless the barrel is IN the upper receiver. Check out the flange that I'm talking about: It's not minor, either - and it's not "standard" on a .308AR. Nobody can give you a number on that thickness, and even if you had it, you can't calculate it to try to time a barrel nut beforehand. Look at this thing: That flange is what the barrel nut locks to your upper receiver. Quote Link to comment Share on other sites More sharing options...
NcPC Posted April 15, 2020 Author Report Share Posted April 15, 2020 Thanks for the pics. I haven't completely stripped an ar yet. But I've see the flange on the barrels didn't even dawn on me the BARREL nut actually was for the barrel Quote Link to comment Share on other sites More sharing options...
PaddyMac Posted April 15, 2020 Report Share Posted April 15, 2020 10 hours ago, NcPC said: Didn't even dawn on me the BARREL nut actually was for the barrel 😁 So once you get your barrel put some anti-seize (very little) on the threads of the upper. Torque to 35lbs in 20-25-30-35lb stages. Each time unscrewing the barrel nut with a breaker bar (not your torque wrench) before going to the next stage. This seats the threads. Torque to 35lbs and inspect gas tube alignment. I don't know anything about your guard but here's where I would start following the guards instructions and using the shims to get things lined up. You'll have to continue to torque upwards until everything lines up. It should line up at some point between 35 and 80-90. I hear you can go higher but I'd be scared for my upper. Others will chime in to help if I made any omissions. Quote Link to comment Share on other sites More sharing options...
PaddyMac Posted April 15, 2020 Report Share Posted April 15, 2020 Oh... I use blue locktite on my gas block screws. Same for guard screws but not until its perfect. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted April 15, 2020 Report Share Posted April 15, 2020 1 hour ago, PaddyMac said: I use blue locktite on my gas block screws I like Rocksett for screws that will be subjected to extended heat. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 16, 2020 Report Share Posted April 16, 2020 (edited) 5 hours ago, PaddyMac said: It should line up at some point between 35 and 80-90. 30lb/ft to 80lb/ft is the M16/M4 Spec. The same should follow on the .308ARs - if we had a spec to follow. Unless your handguard manufacturer specifically states something direct, like 50lb/ft. 30~80 will get it done, lined up, and works on every small-frame AR (M16 and M4) out there in military service. Edited April 16, 2020 by 98Z5V Quote Link to comment Share on other sites More sharing options...
NcPC Posted May 2, 2020 Author Report Share Posted May 2, 2020 Hey everyone I finally received my barrel after some shipping hang ups. Worth the wait! Here is the finished build with the exception of after market trigger that i recently purchased on sale at midway... can't get photo to upload. Quote Link to comment Share on other sites More sharing options...
NcPC Posted May 2, 2020 Author Report Share Posted May 2, 2020 Quote Link to comment Share on other sites More sharing options...
Rsquared Posted May 2, 2020 Report Share Posted May 2, 2020 Lookin good. Quote Link to comment Share on other sites More sharing options...
sagebrush Posted May 2, 2020 Report Share Posted May 2, 2020 nice looking rifle👍 Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted May 3, 2020 Report Share Posted May 3, 2020 Looks great! Quote Link to comment Share on other sites More sharing options...
Cunuckgaucho Posted May 3, 2020 Report Share Posted May 3, 2020 Looks great and you can take it out and shoot it... yeah I'm bitter but not at you @NcPC Quote Link to comment Share on other sites More sharing options...
NcPC Posted May 3, 2020 Author Report Share Posted May 3, 2020 Thanks for the compliments definitely my new favorite gun if there is such a thing 🤔👍 Quote Link to comment Share on other sites More sharing options...
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