TRIARC Systems Bolt Carrier: A Quick Look

[Molon]

TRIARC Systems Bolt Carrier: A Quick Look

For some time now I’ve been interested in trialing a bolt carrier that has been coated with NP3 (electroless nickel TEFLON). NP3 has attributes that are potentially beneficial to the reciprocating parts of the AR-15 such as the bolt and bolt carrier. A relatively new company with a growing reputation for quality called TRIARC Systems sells just such a bolt carrier.

The TRIARC bolt carrier weighs the exact same amount as a full-auto Colt bolt carrier; 9.4 ounces. The carrier proper is made from case hardened 8620 steel, while the gas key is made from 4140 steel. The gas key is fastened to the carrier using Grade 8 hardware. The aft section of the bolt carrier has a small radius on the external diameter to aide in the smooth entrance of the bolt carrier into the receiver extension/buffer tube.

The staking on the gas key is some of the nicest that I’ve seen.

The NP3 coating on the bolt carrier gives the carrier the most lubricious feel of any bolt carrier that I’ve owned; including my JP Enterprises bolt carriers.


The length of the TRIARC bolt carrier is 6.672”, which meets the US mil-spec. The internal diameter of the gas key is 0.181”, which also meets the US mil-spec.


The bore of an AR-15 bolt carrier can be thought of as being divided into three different sections with critical dimensions. Starting at the front of the carrier, the “bolt run” section of the bolt carrier interfaces with the “land” on the bolt. This section of the Triarc carrier has an internal diameter of 0.531”, which as before, meets the US mil-spec.


The next two sections of the bore of the AR-15 bolt carrier are extremely important for the proper function of the gas system. The gas system of the AR-15 is commonly referred to as a “direct impingement” system. In actuality, the AR-15 uses a gas piston system with the tail of the bolt and the gas ring section being the piston and the two sections of the bore of the bolt carrier being discussed forming the cylinder.


The second section of the bore of the bolt carrier interfaces with the gas rings on the bolt and this section of the TRIARC bolt carrier has an internal diameter 0.4995”. The third section of the bolt carrier interfaces with the tail of the bolt and this section of the TRIARC bolt carrier has an internal diameter of 0.2515”. Both of these dimensions meet the US mil-spec and when combined with a bolt with the proper dimensions should produce a highly efficient gas system.


It's truly refreshing to see a new company in the AR-15 arena that is straight forward with the customer as to the materials these components are made from. In addition to all of that, the NP3 coating on the Triarc bolt carrier is quite aesthetically pleasing.

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[Molon]

I checked the firing pin protrusion on the bolt that I received. With the supplied firing pin, the protrusion was 0.0295". With a new Colt firing pin the protrusion was 0.0290".

Since I had the bolt disassembled, I also checked the headspace with a 16" TRIARC Track 2.0 barrel. The bolt closed on 1.4646" gauge. The bolt did not close on a 1.4666" gauge.


It is interesting to note that the cam pin hole on the TRIARC bolt does not have relief cuts like a Colt bolt. Neither does a Hodge bolt.

The mil-spec for the inside diameter of the bolt face is .380", with a tolerance of plus .005". The inside diameter of the bolt face of the TRIARC bolt that I received is ~0.3825".

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[Evolution 9]

Thanks for the write up! Informative as usual.

If you try to insert a cam pin into the wrong side of the Colt bolt, you may find that it won’t go in. In some bolts I’ve seen, those aren’t relief cuts, but press marks (similar in a way to staking) to close up that side of the hole enough to prevent improper assembly. I’m not sure if that’s part of the TDP and/or how common it is