barrel profile help

[s2k1]

Help!  I'm building a new .308 AR, based on a Tactical Machining lower + upper (DPMS style).  I've decided on pretty much all of the parts, but need help on the barrel.  Called LW, and for a custom barrel I need to specify pretty much everything about it.  I ordered an adjustable .750 gas block, so I'm good there.  I'm thinking of an 18" barrel with mid-length gas so that I have ultimate flexibility with the gas system.  I'm thinking something in the "medium" profile, but I don't have measurments for this.  Anyone know where I can get the specs that I need for this?

So here's what I'm thinking for the entire build - comments welcome.

Tactical Machining lower + upper

AR Gold trigger

Magpul MIAD grip

RRA A2 stock

Young Mfg carrier (when they get back in stock)

LW custom barrel + matched bolt (question above)

Troy TRX 308 forgrip

BA Battlecomp

Nikon M-308 scope

[Jgun]

You know what they say about opinions, so take this with a grain of salt and don't pay too much attention to my preferences. I just bought the PRS, and although it's pretty heavy, I think the LOP and cheek riser adjustments make it superior to the A2 if you're going with a fixed butt stock. I also just ordered a LW Vartac barrel, and although it was not the exact barrel I would have special ordered, the savings, and the fact that it's an in stock item, were to good to pass up. I think that if you call them up and speak to Woody, he'll b able to help you select a contour that you will be happy with. By the way, don't forget to post some pics of the finished progect. good luck with it.

[s2k1]

Thanks Jgun.  I also considered the in-stock LW Vartac barrel.  Is your build DPMS-style?  Isn't the Vartec cut for the AR-10 and not DMPS?

[Jgun]

Yes, I was told that it would be Armalite pattern, rifle length. But, since a headspaced bolt is included, all that means to me is that I have to order an Armalite, rifle length gas tube (which is about .250" longer than DPMS/SR-25 rifle length tube). Not really a big deal. My upper is threaded for the DPMS barrel nut thread, and the  SWS handguard's barrel nut is DPMS pattern, but the barrel doesn't care what barrel nut is holding it. I've already got a .308 AR I put together, using a MA TEN receiver set (DPMS pattern), SWS rail (DPMS barrel nut), with a Noveske  .308 Afghan barrel (Armalite pattern) and an Armalite bolt carrier group. The only things that I don't do are mix AR 10 BCGs with DPMS pattern barrels, or DPMS BCGs with Armalite pattern barrels, specifically the barrel extensions.

[jeffreyC]

I would recommend a rifle length gas system instead of mid length.

The .308 has plenty of volume and pressure to operate with a rifle length gas tube on an 18 inch barrel.

[s2k1]

Narrowing down choices for my .308 AR. I was originally considering one from LW or a Rainier Match, but now considering going lower end since it may not make sense to practice on such a high-end barrel, considering these will probably be more accurate than I will be for a while. Which one do you guys think I should get? Other thoughts also welcome.

Rainier Arms Select

http://www.rainierarms.com/?page=sho...roduct_id=2690

AR15Performance

http://www.ar15performance.com/308_barrel

[s2k1]

Also forgot to ask, would a Troy Ind .308 TRX 13.8 handguard cover a Armalite gas block?

[Jgun]

If you look at the post by 338fedAR10, responding to the question about usiing the 12 TRX with rile length gas system, 338 says that the 13.8 TRX works out to be flush with the front of the rifle length gas block. below is the original thread title.

  MA-TEN with 12" TRX Rail and Armalite Rifle Lenght gas system