308 DMR Build

[Jerry R]

I am putting together a 308 DMR. Not called that because I ever was, or ever could be, called a Designated Marksman, but because of the desired results I hope to achieve in the quality, and accuracy of the build.

Parts are starting to trickle in, and I will update this thread with photos of parts, and of the assembly as it progresses.

The parts that have been ordered:

Ascend Armory Match Billet Receiver Set – 7075
Rainier Arms AR10 Switch Keymod Rail .308 – 17”
Rainier Arms Ultramatch Mod2 .308 Barrel .800 Gas Block TiN Extension Fluted – 18”
Rainier Arms Adjustable Bas Block Solid Bleed Off .800 Black
I asked Rainier to pin the gas block for me – I do not have a jig for that.
SI UDC Ultimate Dust Cover for .308
Rainier Arms .308 NiB BCG DPMS SR-25 Pattern
Geissele Super Charging Handle
CMC AR-15/AR10 Lantac E-CT1 Single Stage Upgrade Trigger – Curved
Ascend Armory Titanium 50 Degree Short Throw Ambi-Safety
LUTH-AR .308 Rifle Length Buffer Tube Kit (includes Rifle Length Spring and Rifle Buffer)
MagPul PRS Gen3 Stock
BCM Gunfighter Grip Mod-1
AAC Blackout 51T Flash Hider / Suppressor Mount (for use with the 762-SD)
BoBro Precision Optic Mount – 30mm 20MOA

For initial accuracy testing I will pull the Leupold 8.5x25 x 50 AO Target scope off the .243 Prairie Dog rifle (Remington 40XB KS). This scope was sent to Premier Reticle in 1999 for conversion to a 25 to 50 variable. They did an awesome job, but I’m not sure I am a fan of that much magnification. In both trips to Montana, the mirage was VERY noticeable and the high end of the scope was rarely used. However, I will be shooting off a very stable bench at 100 yards, and I think the scope will help my poor old eyes wring out the last drop of accuracy that I can squeeze from the build. This may, or may not, be the final optic solution for this build. I hope to go back to Montana at least once more.

I selected the CMC Curved Trigger because currently I do not have a flat trigger. I may get one in the future and drop it into one of the guns with a “mil-spec” just to see if I like it. But I wanted to build this DMR with a fire-control setup I am very comfortable with, and that means a curved trigger.

I selected the Ascend Armory Receiver Set because of certain unique features and controls. It is an ambidextrous lower receiver, and they have stated they will upgrade the lower (for free) with their ambi-mag release when it is available. The matched set also looks good.

The barrel was selected because I have other Rainier Ultramatch barrels and I am extremely pleased with their accuracy off the bench. If a rifle is accurate off the bench, it will be accurate in the field – in the hands of a rifleman (apologies to the many ladies that are excellent shooters). The barrel has a “.308 Rainier Match Chamber”. Quote from the Rainier web site:

The Rainier Match Chamber is a modified .308 WIN-7.62 NATO chamber to produce ultimate reliability and accuracy shooting both the 7.62 NATO & .308 WIN rounds.

It is (extremely) unlikely that I will ever hump a DMR in the boonies with a spotter and kit, but as Townsend Whelen once said, “Only accurate rifles are interesting.”

I thought about putting another BattleComp 51.30 on this build, but I have a never used AAC 308 mount in the parts box. SilencerCo shipped it with the 762-SD and I did not know it was a package deal, so I bought a mount when I bought the can. My loss then, my gain now.

[FortTom]

Jerry,

This is going to be interesting. Any guesstimate on when it will be completed? Have an ulterior motive for wanting to see the end results, especially the accuracy aspect.

FT

[Jerry R]

Any guesstimate on when it will be completed?

FT, all the parts have shipped and should be in next week. I hope to complete the assembly that weekend. I am going to GriffonSec's the last week of September/first week of October. Benching will be done then with chrono, GMM, and ball.

[RobertTheTexan]

Looks to be an excellent build Jerry. Looking forward to see the completed weapon.


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[Joelski]

Very interesting!

[FortTom]

I understand the "mature vision" thing, but damn, that's going to be a lot of scope

FT

[Jester Gunwerkz]

Subscribed.

[BoilerUp]

Sounds like a great build.

I like the BCM Gunfighter grips for carbines, but don't care for them much for bench rest shooting. I prefer the Ergos for that.

[Jerry R]

Most of the remaining parts are scheduled to be delivered tomorrow, and another round of photos will begin.

But before that, I wanted to say Thank You to the team at Rainier Arms, and specially to UWone77. The insight, advice, and assistance (that is not seen in this thread) has made this build possible. I have cobbled together a lot of AR-15's, but this is my first non-factory AR10. Subtle nuances such as differences between receiver types, what fits with which type, and on and on ... generates the need for lots of research, or VERY knowledgeable friends that are willing to take the time to help.

So ...

Thank You !!

[Joelski]

Can you publish the knowledge you've amassed? It would sure help those of us that are hung up on the whole Armalite vs. DPMS pattern thing.

[gatordev]

Can you publish the knowledge you've amassed? It would sure help those of us that are hung up on the whole Armalite vs. DPMS pattern thing.

Technically it's "...the whole Armalite vs. DPMS vs. KAC pattern thing." I think a lot of times the KAC pattern is what causes a lot of the confusion, since it's sort of a hybrid of the other two patterns.

[Joelski]

Technically it's "...the whole Armalite vs. DPMS vs. KAC pattern thing." I think a lot of times the KAC pattern is what causes a lot of the confusion, since it's sort of a hybrid of the other two patterns.

I would rather have Aero or CMT's interpretation of the DPMS vs. Armalite thing. If I had KAC style cash to spend, it would be a line-built SR25, no question.

BTW: Did anybody cash in on yesterday's Aero email deal of a complete AR 10 receiver set in FDE for $299?

[gatordev]

I would rather have Aero or CMT's interpretation of the DPMS vs. Armalite thing. If I had KAC style cash to spend, it would be a line-built SR25, no question.

I can understand that and totally understand budgetary restraints. But Mega puts out a good product, and they follow the KAC standard (with a sprinkle of AR-15 in there), so there's still options. Or you could go with LMT, but then you have to buy a NF 2.5-10x24 to keep up with your internet friends. Or so I've heard.

[UWone77]

I can understand that and totally understand budgetary restraints. But Mega puts out a good product, and they follow the KAC standard (with a sprinkle of AR-15 in there), so there's still options. Or you could go with LMT, but then you have to buy a NF 2.5-10x24 to keep up with your internet friends. Or so I've heard.

Heh, you get a guy to buy a 416 upper and the next thing you know you, I keep getting some passive aggressive shade thrown my way

[Joelski]

I can understand that and totally understand budgetary restraints. But Mega puts out a good product, and they follow the KAC standard (with a sprinkle of AR-15 in there), so there's still options. Or you could go with LMT, but then you have to buy a NF 2.5-10x24 to keep up with your internet friends. Or so I've heard.

I'm liking the MWS, but if I get that, I'll have to rely on my awesome internet friends to hook me up with the NF glass.