Upper receiver options for precision build

[opngrnd]

I have a 15" Geissele Mk8 rail on my 18" precision build, and a 13" Mk8 on my 16" precision build. I've been satisfied with them. If I were doing it again, I'd probably go with a rail that has external attachment for the Bipod, such as the DD Lite 3 DDM4 rail, or the Geissele Mk13.

Will you be doing your shooting mostly from prone? Ergonomics may not matter as much to you, which might push you towards a quad rail. I know with my 18" SPR, I could have done the quad because it's always shot from prone and the ergonomics don't matter. Just food for thought.

[jhr1986]

I have a 15" Geissele Mk8 rail on my 18" precision build, and a 13" Mk8 on my 16" precision build. I've been satisfied with them. If I were doing it again, I'd probably go with a rail that has external attachment for the Bipod, such as the DD Lite 3 DDM4 rail, or the Geissele Mk13.

Will you be doing your shooting mostly from prone? Ergonomics may not matter as much to you, which might push you towards a quad rail. I know with my 18" SPR, I could have done the quad because it's always shot from prone and the ergonomics don't matter. Just food for thought.

Will mostly be shot from the prone and bench. Probably less than 10% will be positional or from a barricade/tree/rock.

The MK13 looks good in terms of bipod mounting.

The products from Barnes Precision Machine and Hodge have also caught my attention but I have heard very little feedback on the former and the later seems to be continually OOS so again not a ton of feedback on those either.

[jhr1986]

Little update on this; got the MUR and BCM uppers in along with some other parts. I don’t have a standard stripped upper to compare these directly to but the BCM has more material (thicker walls) right behind the barrel nut threads.

The MUR upper weighs more according to my hand scale, but doesn’t have thicker walls right behind the threads - it seems to be same as the milspec uppers for the first 1/2” behind the threads.

I would think extra material in this area would be important for adding support for the barrel.

The Noveske branded MUR upper looks like it does have more material here so I might pick one of those up also to compare.

I’ll take a few pics tomorrow to illustrate the differences.

Most other parts choices are finalized:

Bartlein barrel from Craddock
JP fmos bcg
Leaning towards a URX 4 rail, but mk13/14 is still in the mix

Will probably order the barrel next month so hopefully I’ll have a range report to share sometime in the spring.

[GunFighter98]

The Noveske version of the MUR has even more material around the barrel extension. This would be my preferred option.

[jhr1986]

Little late getting these pics but as you can see, the BCM upper has more material in the area surrounding the barrel extension than the MUR upper.

I was hoping the MUR upper would mate nicely to the Noveske lower i have lying around but I'm not totally happy with the fit. Upper/lower fit and matching aesthetically are secondary concerns and I wasn't really planning on using the Noveske for this build but a nice match between the two is always a bonus.

Still undecided on the upper/lower combo to use for this build but I'm kinda leaning towards the Aero lower and BCM upper right now.

The last (4th) pic is of the Noveske marked MUR upper (from Rainier Arms' website), and it also has more material right behind the barrel nut threads. I may pick up one of these as well to compare to the other two before I make my final decision.

Other parts are starting to come in as well; I need to go ahead and order the barrel to get the wait started on that.

Mods, feel free to move this to General as it's becoming more of a build thread and less of a tech discussion.

[bruin]

I’m wanting to build an AR that is as accurate as I can make it.

IMHO spend as much as you can on the barrel and direct thread your suppressor. Sounds like you already got the quality trigger aspect covered, and hopefully handloads as well. Thermal fit BE to upper is preferable over shims or Loctite, so the BCM upper has the advantage there.

I doubt that the extra material behind the barrel nut makes a significant difference. MURs have suffered documented KBs and are likely sufficiently robust in that regard. Carry handle uppers tested with noticeably less flex than milspec flattops, though the profiles below the rail are identical. I'm guessing you plan to mount a scope on this; a one-piece mount will further stiffen the upper. As a practical concern the BCM and Noveske limit your rail choices, but you will want a stiff handguard for bipod loading, etc.

Good luck with your build, and let us know how it turns out!


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[markm]

I'm wondering what the end use of the rifle will be. A recreational "hole stacker"? Competition gun? Hunting rifle? etc?

I've seen Colt 6940s that with good ammo, will hang with any custom built gun at 3 times (or more) the price. Guys here were swearing by the Colt SOCOM barrels too.

Uppers and all that stuff might make a big difference to Camp Perry type shooters. But with good ammo, I've seen a lot of plain jane ARs that had outstanding accuracy.

(I do, based on the builds I've done, like the Geissele rail and upper option mentioned in the original post.)

[jhr1986]

recreational "hole stacker" is exactly what I am going for

[MistWolf]

The Noveske MUR upper has more material to make up for the fact it's billet. Forged receivers are generally stiffer than billet receivers because the grain follows the shape of the part. The grain in the billet runs just runs straight. Machining the parts cuts across those grains.

The VLTOR MUR is forged.

[GunFighter98]

The Noveske MUR upper has more material to make up for the fact it's billet. Forged receivers are generally stiffer than billet receivers because the grain follows the shape of the part. The grain in the billet runs just runs straight. Machining the parts cuts across those grains.

The VLTOR MUR is forged.

Noveske MUR is also forged.