Hello, I'd like to build a highly accurate 6mmARC for more precision shooting... Kind of a coyote hunting/precision set up. I'm using a 20" SPR profile barrel. I've heard heavy barrels and/or bipod loads can cause POI changes. I've read a lot of posts but noting definitive. I'm trying to decide between a thermofit BCM receiver w/ the DD MFR XL rail. Or, the Aero Precision ENHANCED receiver and Handguard. I've handled the AR Enhanced and was not thrilled w/ the large girth of the Handguard. But, if it would be better for my setup, I'll deal w/ it.. Your thoughts and input are appreciated.
- Thread starter RemoteDoc
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Your barrel what size gas block does it use, and were you going to use an adjustable gas block?
I’d buy a Mega MML, Seekins IRMT-3, or Larue Stealth 2.0 over either of those.
I went back and forth on building one and ended up just buying a complete Seekins rifle because I couldn’t build one of the same quality for what it cost and it’s a factory rifle from a company that will stand behind it if there’s an issues.
I went back and forth on building one and ended up just buying a complete Seekins rifle because I couldn’t build one of the same quality for what it cost and it’s a factory rifle from a company that will stand behind it if there’s an issues.
0.750 non-adjustable gas block on 20" SPR profile Ballistic Advantage barrel.
Thanks! It looks like Seekins only offers the 6mmARC in 22". I'd like to stay with 20".
I avoid Larue stuff at all costs... I like to know what I'm buying. 4-groove, 6-groove, 3R, 5R, 4140, 4150, Stainless, Melonited, etc... Larue won't tell any of this info to potential buyers. They stick to the "trust me; the check is in the mail" approach. It reminds me of when you get off the bus in Mexico; everyone has a "deal just for you". lol. Even cheap manufactures advertise their quality goods. In today's marketplace I figure only someone trying to pass off crap would hide such details from consumers.
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The Rainier Arms brand uppers are solid. I have quite a few I've built off of, including my 6.5 Grendel DMR, and that rifle shoots sub-1/2 MOA with handloads. The Aero Precision M4E1 Enhanced uppers are also very nice for forged uppers. I have a few of these, as well. All those rifles shoot very well for what they are (8" & 10" .300 BLK's), but they use a proprietary barrel nut mounting system that requires you to use the Aero Precision Enhanced hand guards, of which they offer many different options. The Aero threaded (standard) M4E1 uppers are also very nice machining, and use regular barrel nuts and hand guards.
Personally, I'd go 15" handgaurd regardless of which way you go.
www.rainierarms.com 
www.aeroprecisionusa.com 
www.aeroprecisionusa.com
Personally, I'd go 15" handgaurd regardless of which way you go.
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www.aeroprecisionusa.com Seekins does it in 18” too, that’s what mine is. I wanted 18 because that’s the length the cartridge was developed around. Pretty sure their custom shop can do whatever you want as well.
Both of my Larue MGU’s are stamped on the barrel what they are and both are hammers. Besides if you buy the stealth receiver you’re not even using their barrel. It’s a great receiver and absolutely top tier, more so than either the BCM or Aero you’re looking at.
I'm working on my second build using the Aero Enhanced upper with the proprietary freefloated handguard. The handguard attaches by fitting into grooves or notches for anti-rotation and are secured by eight screws. This system is strong and precise in the way it all fits. Aero Precision has excellent products.
And the first barrel is a Compass Lake Douglas 20 incher, tactical contour. It gives nice ragged .7 ten shot groups with 77 gr. Sierras and 24 grs. Varget. Looking for second barrel after Christmas.
And the first barrel is a Compass Lake Douglas 20 incher, tactical contour. It gives nice ragged .7 ten shot groups with 77 gr. Sierras and 24 grs. Varget. Looking for second barrel after Christmas.
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OK so you have two things going for you. Your combo should fit under any slim handguard that's out there. And I doubt the barrel would make contact with the handguard when you're shooting it. But a bigger diameter handguard would guarantee you wont have issues. That said I do believe that a heavy walled upper with the oversized handguard mounting like the Mega's, Seekings, Vltor, Aero enhanced will make a difference in the amount of flex the handguard has. Another aspect of the thicker upper, it won't flex as much when the barrel whips around after being fired simply because there's more material for strength.
Some other upper receiver/rail combos that looked interesting to me is:
Ballistic Advantage logic rail on a aero e4 upper,
The 360precision units https://360precision.com/product-category/ar-parts/,
Cobalt Kinetics Billet Upper Receiver with Proprietary Handguard,
Noveske,
LaRue Stealth 2.0 Upper Receiver and Handguard,
AT3 Tactical Complete Upper Receivers,
Personally I'm using a Mega billet upper, and I just ordered the white oak armament handguard because I need the hand guard to stop behind the .875 gas block on my heavy 6mm arc barrel.
If youre going with a Ballistic Advantage barrel, you have already started on the wrong foot. Aeros m4e1 upper receiver will work just fine. I would spend more money on a barrel though.
I used a Seekins upper with the integrated hand guard nut. it was much more solid than the upper I had used before. I used a proof barrel, but if I was going to do it again, I would go with Craddock precision. I use and H2, full mass carrier, and adjustable gas block.
good stuff right there. Seekins upper with their handguard is great stuff.
The 360Precision units are legit. I have one of his combo sets and it’s really nice.
I also like BCM uppers. $49 blems right now and thermal fit.
People talk shit about Faxon, but I have a 416r stainless & fluted Faxon 5R Heavy Match barrel on my 6.5 Grendle DMR, and it shoots amazing with handloads.
I'll echo the others & suggest you get a different receiver
Geissele Mk1 Mod 0 & Mod 1 are the most comfortable rails out there, in my opinion. They're slightly narrower than the Mk4s & have radiused sides/bottoms (not the best to bolt an ARCA to)
That said, good luck finding one at a decent price
Also, a pre ZEV Mega Monolithic MTS-400 single rail
Geissele Mk1 Mod 0 & Mod 1 are the most comfortable rails out there, in my opinion. They're slightly narrower than the Mk4s & have radiused sides/bottoms (not the best to bolt an ARCA to)
That said, good luck finding one at a decent price
Also, a pre ZEV Mega Monolithic MTS-400 single rail
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Seekins (not my pic)
I'm running a Aero enhanced upper, Sgt of Arms ARCA 17.5" handguard, 20" carbon proof for my 6 ARC and love it.
I missed the ballistic advantage barrel. At that rate just get anything because it’s not going to make a difference.
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