Do it yourself 308 AR-10 Rifles

With the onset of DPMS style AR-10’s hitting the market, we take a look at CMT’s new 308 Stripped Billet offering.

Cross Machine & Tool (CMT) is a Veteran owned and operated business based in Lexington Tennessee specializing in Billet AR-15 and now AR-10 receivers.

CMT uses state-of-the-art CNC machines to turn out what some say is one of the best AR-15 billet sets on the market. They are no stranger to the AR world as they manufacturer for several OEM’s as well.

The CMT Billet Combo Receiver, a UHP10 Lower Receiver coupled with the UPUR10 Upper Receiver, is CNC machined from 7075 T-6 Billet aluminum and it type III class III hard anodized.

CMT chose the DPMS high profile rail height platform because of the enormous support for parts and accessories widely available.

For those wanting to build their first .308 semi-automatic precision rifle, the CMT is a great choice as the lower will take a standard AR-15 lower receiver parts kits sans the bolt catch and take-down and pivot pin, those are AR-10 specific, but everything else is the same. The upper is compatible with all DPMS high profile 308 handguards such as the Centurion Arms CMR rail. The upper also requires a DPMS 308 bolt carrier group, charging handle, dust cover kit and there is no forward assist.

Rainier Arms received the first shipment last March. The combo set sells for just $498, which is the least expensive billet 308 I have seen to date.

I decided to build one out which proved to be a fun project and not all that different from the AR-15 build process.

Build Notes

One of the things that I absolutely love about CMT’s design is the bolt catch assembly is held in place with a removable Hex screw rather than roll pin, which makes for nice and easy installation. The flared Mag-Well is also wire EDM cut, so my PMAGS fit like a glove as well as Lancers new 308 mag. Another feature I appreciate in the design is the upper tension screw built into the lower so that your upper to lower fit can be tightened.

Specifications

CMT UHP10 DPMS 308 Billet Set

Rainier Arms 18” 308 Barrel

Rainier Arms 308 Raptor Charging Handle

Centurion Arms CMR 308 Rail

BattleComp BABC

BattleArms Bad Ass Safety

Magpul UBR Stock

HERA Arms Grip

Seekins Precision Mag Release

DPMS 308 Lower Parts Kit

Redfield 3-9 Scope and Leupold Mark 4 CQ/T

The lower went together just like any AR-15 I have ever built and I had no issues with fit and finish. The upper requires a 308 dust cover and pin, which are captured on both ends, so installation was super smooth and fast. I chose a Rainier Arms fluted 18” 308 barrel for this build. The barrel was pretty tight and had to be hammered in, something I never enjoy. I tried a few different barrels just to check fit and they were all pretty tight. After applying a little lube and getting the barrel extension lined up, I was able to get it in.

For the rail, I went with the Centurion Arms CMR 308 rail, which does not require a timed barrel nut, so installation was piece of cake and took all of 2 minutes. The last piece was adding my BattleComp BABC 308 muzzle device.

At The Range

As expected the CMT rifle performed well without any FTE’s or FTFs. Recoil was very manageable for our test group, which ranged from guys of all sizes. We were not testing for accuracy due to time constraints, but that is next on my list.

Special thanks to Praetor Defense and Chris Tran.