AR Sponsor
Posted: 10/27/2014 4:49:56 PM EDT
|
Hello all,
I have a Stag M4 build I am using a 16 inch Douglas MB and UTG long free float hand guard, I think 15inch in length. I have shot this rifle already and seems to shoot with Tula steel ammo OK. The question I have is a 2 fold one. 1. In the picture below, is the hand guard suppose to be flush with the receiver? 2. If so, does this mean that the barrel nut needs to be re-seated in order for the the hand guard to sit flush? 
I believe I have the barrel nut torqued to around 50 ish ft lbs. The reason is two fold as well, first, looks. Second I saw a youtube video of someone with more experience than I installing a barrel nut and mentioned that the receiver threads need stretching. I did not do this and am wondering if I need to do that to see if the hand guard will sit flush after doing so.Can someone shed some insight on this? Thanks, Mark |
|
Second I saw a youtube video of someone with more experience than I installing a barrel nut and mentioned that the receiver threads need stretching. LMAO. Ignore that yahoo. 7075-T6 really doesn't stretch, and you'd crack the upper long before deforming threads. Torque to yield is common in automotive, but it's stretching the entire fastener, not the threads. In point of fact, virtually all assembly with TTY fasteners indicates lube on the threads specifically to mitigate damage to the threads. As for your barrel nut, are you sure there aren't shims hanging out on the barrel flange? That said, I've installed several of the UTG FF rails, they all do have a small gap between top rail and receiver. |
|
tapered-pin,
I am assuming when you say indexed, you mean that it is oriented correctly. Well, the hand guard can only go one way as to allow the gas block feed through. So I am hoping that is what you mean. I was trying to see if I can somehow adjust the mounting collar to move it forward, but no luck there. Mark |
|
Quoted:
tapered-pin, I am assuming when you say indexed, you mean that it is oriented correctly. Well, the hand guard can only go one way as to allow the gas block feed through. So I am hoping that is what you mean. I was trying to see if I can somehow adjust the mounting collar to move it forward, but no luck there. Mark He means indexed as far as the alignment with the gas tube holes and the receiver. If the nut is torqued tight in between the specific torque limits and everything lines up, then you are indexed. I've installed about 4-5 of these. There will be a small gap, but that's it. I feel those nuts are a tad too shallow. |
|
I had it the barrel nut torqued to 50lbs lined up with the gas tube. I then took it off and then re-tightened it to about 70lbs to get to the next hole over. Not much closer on the rail. I will leave it and will probably need to re-adjust the site since POI probably changed, but oh well, another reason to shoot it I guess. My next upper build I will probably look for another rail that will sit more flush, unless there is a reason that I don't need to. By they way, what should I be looking for in barrel nuts, or are they all pretty much the same across the board?
Mark |
AR Sponsor