So, I'm building another AR-15. I tried once before, and that gun is not living up to my accuracy expectations, you can say I'm a bad shot, on most days you'd probably be right, but I, nor any of the other excellent shooters I've had try can wring better than 2-2.5moa out of it. The definition of insanity is doing the same thing over and over again while expecting different results, so I decided to build another AR ;)

I've bought all the parts, and my receiver and handguard are going for cerakote next week. I'm trying for maximum accuracy in a lightweight, compact package this time.

So, my question is does it make a huge difference who puts this thing together beyond torquing things to the correct poundage?

I kinda think it does. So, if it matters, who should I have do it? Assuming it matters, who is the accuracy king of AR smiths?

I know everyone says how accurate the AR is, but I just haven't seen it yet, I've got a lot invested, and I'd like to make sure I get the best accuracy out of it that I possibly can, so any help or opinions would be greatly appreciated!

 

Here's my parts list for reference:

Upper

Silencerco ASR Trifecta Flash hider

Battle Arms Development (BAD) 14.5 Lightrigid Barrel

SLR Rifleworks Sentry 6 Ti Gasblock set screw

V7 Extreme Gas Tube Mid-length

BCM KMR Alpha 13” Handguard

BAD LW Billet Receiver set

BAD Ti Take-down Pins

BAD M16 Bolt Carrier Group

V7 Ultralight port door

AXTS Raptor Charging Handle

Lower

V7 Ultralight Bolt Catch

V7 Ultralight Mag Catch

BAD Safety selector

Geiselle SD-E trigger

Umbrella Corp Grip

V7 Buffer Tube

V7 Buffer Retainer

V7 Endplate/castlenut

Mission First Tactical Minamalist Stock

That barrel better shoot for the price they're asking for them.

What barrel is on your other rifle?  Try different factory match and handloads?  Try pulling the barrel off and reinstalling, perhaps with different amount of torque?

There's not a lot you can do when putting am AR together to help it's accuracy. Biggest thing I can think of that may help is squaring the receiver face, which can be done with a cheap tool from Brownells.  I really don't think it matters who puts it together for you. I'd do it myself again, but I'm stubborn like that.

I am with Danger, here.  Definitely do continue with your current build...but I'd rip apart that other one and I would do th following:  shim the reciever extension to the upper, true the face of the upper, re-install at a good known torque value, install the muzzle brake with rocksett and light torque.



Some of us have had to rip guns apart 3 or more times to get 'em right....and sometimes it's the oddest stuff giving you issues......



Make sure on your new build that the barrel nut gets torqued correct and that the muzzle device is times and set right without too much torque.



Good choice on the trigger, BTW.



 

I'm about to rip apart my .223 wylde SPR for the third time.  It's shooting MOA but just barely and I have a feeling it may have to do with the gas block/gas tube (after reading your post)

While I have it apart I'm going to lap the face of the receiver and bed it in blue loctite as suggested in other threads.  I also plan on drilling the hole in the barrel nut a little larger (its a Midwest Industries FF that uses the YHM style barrel nut) to ensure the gas tube doesn't touch the barrel nut at all.  Also need to measure the gas ports and ensure they are aligned.


The port on the gas block was much larger and covered the gas port on the barrel, I didn't think they needed to be centered. Maybe that is an issue. I think they sit off center because the barrel was originally set up to have a hand guard cap.  The gas block sits flush on the shoulder of the journal and maybe it needs to be set back the width of the hand guard cap.


Thoughts?

Tagged for after work today, definitely!

This is what I mean on the gas port in the barrel and gas block:

Is this ok? As long as there is full overlap?




Or does it need to be like this:

Looks good. I like all the v7 parts. Maybe LRRPF52 will be by to share some of his trade secrets for getting very accurate ar15s.

Ideally, you would want to have the position of the smallest hole co-axially aligned with the center axis of the largest hole...BUT, functionally I have a hard time seeing that it would matter too much as long as the the smallest hole is within the circumference of the larger.  The overlap area is still the same amount of area, it's position is just not true to the theoretical datum axis that we would like to have both features line up with.



 In the end, the flow should be the same, though the dynamics might be just a bit different, the amount of area we are talking about is so small compared to the volume of gas, that I can hardly see that making a difference.



HOWEVER....if the gas block is set BACK toward the carrier, then the gas tube has set back by that distance, and, in my case it was by a LOT. Remember, I was using a NON-standard gas tube pattern and matching block by Wilson Combat  I have a feeling that if I had used a Wilson Combat barrel, I would have had no alignment issues to begin with and would not have milled the block to line up the holes.  Nearly 40 thousandths is what I removed from the back of the block to get the positional alignment....which, no matter what I did, left me with an impingement upon the carrier key which was visibly discernible at the correct angle.  So, let's say you have a small amount of impingement.  My experience shows that you can re-radius the ball at the end of the gas tube ( the part that goes into the key ) by OVER 20 thousandths and, if you radius  it correctly and shape the lead angle, you still have a system that will function....but if you have any impingement that puts any amount of undo force on the gas tube it WILL affect cold shots AND groups as you have seen in my pictures.



I have more on this entire concept but I don't want to unduly hi-jac the OP's thread.



OP, forgive me for the hi-jack but DO read what Ranger and I are discussing because if you or your friends are into building AR-15 and AR-10 precision platforms, weird stuff like this comes up.



Ranger....we should start some kind of barrel "system" type thread where we get itno EVERYTHING about installing barrels nd blocks and the issues we have had.  It would be a great thread.  What do you think?



 

I love it.  There are so many specific "smith" issues dealing with gas guns on a precision platform.  Being that a good barrel is part of the tri-fecta of precision in any rifle, and a barrel on a gas gun has many unique issues, this idea for a separate thread is a great idea.

Should we do it in this forum?  It really applies here, specifically because we are discussing gas flow, harmonics, etc.



What do you think?