Mini Review / First Impressions TriArc (Feddersen blank) barrel. 12.5 mid gas

Ok posting this as a new thread due to interest in the TriArc barrel

In my search for a sub moa 11.5 to 12.5 barrel I got many great suggestions and decided on TriArc due to reports of super high accuracy across a broad range of ammunition as well as being a soft shooter

I received and built up my TriArc (Feddersen blank) barrel. 12.5 mid gas

First impressions were that the barrel is devoid of markings. The only markings are on the barrel extension end. A small S on the left at 6 oclock and a small 4 on the right at 3 oclock. Anyone know what these denote? Also included were some stickers (lol?)

I measured the gas port with my OriginCal (certified) but it's not the best way to measure as it's not the exact diameter due to the offset tips of the internal?
Anyway - I got .073 and .075 measuring twice.

My SLR7 Sentry Ti adjustable gas block slipped right on

The barrel was pre-dimpled through the nitriding which was surprising. I'll need to grease that dimple to prevent rust right?

Weight was right at 662g (1 lb 5.94 oz) which is 21.94 oz

Heavier than my Spikes/FN 11.5 pencil which came in around 17.496oz. The TriArc looks like an HBAR next to the Spikes/FN pencil LOL
I am a bit disappointed as the TriArc site advertised the barrel at 1.37 lbs and this is 1.46 lbs. Looking back on the site, I see all the barrels up to the 14.5" are advertised at 1.37 lbs. The 16" says 1.71 lbs

That seems a bit sloppy at best and sketchy at worst.

I have Reman Black Hills 77gr OTM, 55gr IMI and 62g MagTech right now. If anybody has some favorite commercial ammo they'd like me to test I'd be amenable.

I'm planning on ordering some IMI 69gr RazorCore (77gr is OS) and some Speer Gold Dot LE 75gr SP unless someone says otherwise?

Upper Build List:

TriArc 12.5 Track 2.0 Barrel 5.56/Midgas
San Tan Upper receiver billet
2A Balios Lite 10.0 MLok Rail / AL Nut (Seasoned 3X and Torqued to 45ftlbs)
SLR7 Ti adjustable gas block
Brownells Nitride LW BCG
Griffin Stealth Flash Hider

Info from TriArc site

Length 12.5"
Material 4150V grade Milspec B-11595E Chromium-Molybdenum-Vanadium (CrMoV)
Profile TRACK
Finish Nitrocarburizing ( BLACKNITRIDE™ )
Extension Finish Np3®
Gas System Mid-Length
Gas Block Journal .750" Diameter w/ 1" Length
Twist Rate 1.7"
Muzzle 1/2x28 Threaded
Weight 1.37 Lbs
Other Info Barrels are turned on centers and never chopped down from longer lengths
Patent Number WO 2013074132 A1

Garand Thumb did a review on YouTube of a Triarc setup. I don't remember which barrel length though.

Check it out, he had good things to say.

Sent from my Pixel 2 using Tapatalk

Just got back from the range. Not too exciting, it's indoors and max of 25 yards and dimly lit.

This was just a gas block tune and function test of the build. Rough RDS sight in for 50 yard zero.

However, compared to my Spikes/FN 11.5 build this TriArc Track 2.0 barrel seems to group much tighter

I used the brass clock method to tune the gas.

Forgot to mention my SLR7 Gas block adjustment

Using the "brass o-clock" method I set it 10 clicks from fully closed to get ejection to around 3 oclock.
Tried to use carbine buffer minus weights plus regular carbine spring and got some instances of the bolt not fully cycling. Pushing / denting rounds
Finally settled on Using regular carbine buffer and spring
Brownells Light Weight Nitride BCG

Quote:

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Originally Posted by joeg26er

First impressions were that the barrel is devoid of markings. The only markings are on the barrel extension end. A small S on the left at 6 oclock and a small 4 on the right at 3 oclock. Anyone know what these denote? Also included were some stickers (lol?)

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Those markings are a manufacturer variant of "M4" markings.

Any further updates on this?

Quote:

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Originally Posted by joeg26er

Forgot to mention my SLR7 Gas block adjustment

Using the "brass o-clock" method I set it 10 clicks from fully closed to get ejection to around 3 oclock.

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Ejection pattern is an unreliable way to tune your gas block. To properly set the gas block, load a single round in the mag, load the AR and fire it. The AR should eject and lock back. Keep closing the gas block until the AR ejects but does not lock back. Open the gas block one click and verify that it will eject and lock back. Then, open it one more click, if needed, to ensure reliable function. If ejection pattern is weak or erratic, replace the ejector spring, then replace the extractor spring with a Colt extractor spring.

Carbine buffers are too light, even with an adjustable gas block. Use either an H or H2 buffer.