6mm ARC Bolt Gun Complete

[Old Bob]

I finally got my Uintah 6mmARC bolt gun built. Parts List:

Anderson lower receiver put together with Anderson lower parts except the trigger.

The Uintah furnished 3.5lb single stage trigger.

A fixed Magpul Carbine stock* with a Sylvan Arms side folder adapter (wanted a Law Tactical adapter but couldn't find one anywhere).

Leupold 4.5-14x50 Mark 4 scope with a Leupold scope mount (might change the scope mount to a Wilson Combat V3 Ultralight AR Scope Mount). Burris Tactical 30mm rings.

Wilson Combat Q-Comp muzzle brake.

* I tried a G.I. A1 stock first but it was way too long with the adapter.

Getting anxious to do some trigger time on this rifle. Won't be able to get out to the range until Wednesday...

[SBRSarge]

Looks nice. I’ve heard some folks say the folding adapter is silly on a longer rifle like that. But I think they’re thinking of it being on an uber shorty that you carry in a backpack. I think it is a perfect addition to a longer gun to make it more portable, especially if a can ends up being screwed onto it.

[Dino11]

I was at the range a couple days ago, put the Uintah billet lower on it with the Velocity trigger.

Not sure I like the trigger, I am more into 2 stage triggers for precision rifles. The lower that I used on the first outing had an MBT2s in it. It is on the do not use list but it functioned perfectly. I like the 2 lb. pull of the second stage in that trigger. Maybe I am just used to using them, not going to switch it out yet.

We were fighting 20 to 25 mph winds. When we first got there it wasn't to bad but the wind picked up in less than an hour of getting started. Still had a great time and the barrel is still shooting .5 MOA or less after nitrideing, copper build up is  almost non existent and it is very easy to clean.

Interesting note though, I was seeing velocity in the high upper 2700 fps to low 2800 fps with the factory ammo. But I also got a couple in the high 2600 fps.

[SBRSarge]

Dino11,

I’m still thinking about nitriding my barrel. How much did that cost? And about how much did you see the fps jump, if any?

[Old Bob]

SBRSarge... That is the reason I installed the adapter... to make the rifle a bit more portable. Look at the third photo. You can see a QD sling swivel attached to the latch plate & a Magpul QD adapter on the hand guard. I intend to carry the rifle muzzle down with the stock folded. BTW, the rifle weighs 10.25lbs unloaded.

[Dino11]

Dino11,

I’m still thinking about nitriding my barrel. How much did that cost? And about how much did you see the fps jump, if any?

The cost was 125.00 out the door, company is local to me and I dropped it off and picked it up, 10 day turn a round. Their are other outfits out their that are a little bit cheaper, but the folks at H&M Metal Processing do the best work I have seen.

I think it is to early to tell what velocity I will see, I only have 120 rounds down the barrel. But judging from the other barrels I have I would say around a 300 fps increase at this point in time. But some of that might be due to the extra 4" of barrel length. I need to get the 20" barrel to the range and chrono it. I have only put 60 rounds through it testing it for function and zeroing. It just sits in the safe. Maybe I should just sel itl, this one is built on an A2 platform. I don't really care much for the scope on it, poor eye releaf on it and makes my eyes tired.

[grayfox]

Both my monster and the uintah will see the target downrange today.
Initial shots for the big "U" and rounds ~20-30 for the monster.
Still doing function and zero checks. Swapped out scopes on the monster.
I didn't like the bushnell nitro 4-16, for my eyes. Nice enough but just not there, you know?
the 20" monster, 9lb 3 oz.
the 22" uintah. 9lb 12 oz.

[grayfox]

So. Did some first-shot breakins, and zeroing of scope for both barrels.
The Uintah is really nice! 2 groups at the end of its workout, one with Eldm-108 (factory) 0.6 moa, and one with my hand load 103 Eldx (I was hoping it would work for both of these) - 0.75"/100 yd.
Now to be fair the first one was only at 50 yds but still 0.3", 3-shot. Getting used to scopes as well as barrels.
My 20-Monster, I had some time left so tried a few down range. One set of 4 came in at a 2x2 pattern, ~1.3" but I was getting a little tired (eyes) and the butt stock I have on it isn't my favorite... so. These clock at 2681 in the faxon-20 so I expect/hope similar for this one... and Grt says they are at 2740 in the Uintah... although I think more like ~2720, for those extra 2 inches.

The uintah did have a couple 108's that were difficult to pick up/feed, I had to jiggle them in. 2 of them I think. None of the 103's had any problems.

Still, having one load that is promising for both my babies.... YEAH!!

Chrony and dialing in of loads, on the horizon. For both of these guys.

[alwie]

So.  Did some first-shot breakins, and zeroing of scope for both barrels. 
The Uintah is really nice!

What magazines are you using?

[grayfox]

They are the cpd duramags, 10 rounders.

[Old Bob]

Does anyone know whether the drop-in trigger supplied by Uintah with their upper assemblies is made by Uintah or some other manufacturer? The info on their website says the trigger is supposed to have a 3.5lb trigger pull. The one that came with my upper runs 4.5 to 4.75lbs most of the time but will occasionally reach 5lbs. There's also some slight creep before the trigger breaks. Overall, this trigger is... inconsistent.

The 3lb Velocity trigger they have on their website has good to great reviews but right now, it's out of stock. Fortunately, I was able to find one after searching through several AR15 parts supplier websites. I also considered Rise triggers & would gotten one of them had I not found the Velocity trigger.I have a Rise trigger on one of my other ARs & wouldn't have any problem getting another.

How about Elftmann trggers? Never heard of  them 'til now. Anyone have experience with them?

[grayfox]

Mine came with a 3 lb Velocity trigger. Separate little pkg in the box.
I already have a lower with a Velocity in it so am using that for the rifle.

[Old Bob]

Mine came with a 3 lb Velocity trigger.  Separate little pkg in the box.
I already have a lower with a Velocity in it so am using that for the rifle.

My trigger also came in a separate little package (a plain small, white, unmarked cardboard box). Velocity triggers are green. Mine is gray & has only the Uintah JP logo on it... no other markings. Did you specify the Velocity trigger when you ordered your upper assembly?

Now you're gonna have to build another rifle to put that extra trigger in...

[Dino11]

Mine came with a three pound Velocity trigger. It is a single stage unit and tested to pull at 3 lbs.

When I first got my upper I put it on a lower I already had, this lower had a Larue MBT2s trigger in it. The Larue trigger is on the will not work list they provide in their instructions. But I tested it for function by dry firing it and it seemed to work just fine.

So I took it to the range and put 60 rounds through it with out a single problem. I have since received my Uintah billet lower, I put the Velocity trigger in it and went back to the range. I found that I was more inclined to pull shots with this trigger so today when I cleaned the rifle I put in a Larue MBT2s I had as a spare unit.

It seems to function well during dry fire, and the second stage is pulling right at 2 lbs. I shot the other MBT well on the first outing, and I have really taken a liking to them, as I have them in most all my AR's. For the money you can't beat them, and they get better with use. I might try a lightened JP trigger spring in one of them, I have the JP spring kit already just need to find time to try it out. I would love to see the trigger pull at sub 2 lbs. on this gun.

[grayfox]

The thing they were saying about the "do not work" triggers was they might fire out of battery...
Did you look into that aspect for your MBT's?

Bob, no I didn't specify; it said it would come with one altho' a 3.5, but I like the 2.5-3 lb range better.
Maybe give them a call and see if you can swap it out for the velocity one.

They seemed pretty helpful (I talked to Trish in their customer svc when I called on some stuff).

[Dino11]

The only way to truly test out of battery firing would be with a live round, or at least a round with a primer in it. Both the Velocity and the MBT triggers is they both will trip and send the hammer flying out of battery. But the real question is... does the firing pin hit the primer with enough force to ignite it. That would be a function of the bolt assembly. The trigger will always trip if it has been cocked, unless the safety has been put in safe mode. There is a ramped notch on the bottom of the bolt to prevent the hammer from hitting the firing pin unless the handle is in the proper position. Once the bolt has been rotated to the lock position the hammer can pass the notch allowing it to strike the pin.

[gorillamotors]

I am thinking about getting one of the 6ARC uppers. So do you like the 6ARC upper? And how does it shoot?

[AA1bird]

Just got mine and haven’t had the time to go to the range. Sometimes I really hate work.