Hi all,

I just ordered my 6mm ARC 20" upper tonight, I have been considering this for quite a while. I figured it will fit well with my 6.5 Grendel and 6.8 SPC. For once this is a caliber that I know very little about. I have been handloading for over 40 years. I will be digging around looking for good load data to help me develop a hunting round for this gun. I am very interested to learn what this caliber has to offer.

I just finished my 6ARC 20" AR build and was really wondering what realistic velocities should I expect?

55 gr Nosler BT - IMR 8208. I have shot it with 31 grains and it shoots really well. Did not do any load development, just based it of Hornady max load for the 58 Vmax and it shoots consistently 1" or less at 100yds with 2 different shooters. Myself and the other, my grandson who is a first time rifle shooter.  I plan to run this as my coyote load if the speed is adequate. I suspect it is as I have killed two pigs with it already. Figured I would try it and it worked really good on pigs at 100yds.... Don't plan to use it for pigs however.

100 Sierra SBT - Using Lever. I have put OCW together and running 27.9 grains it was shooting 2484 fps and 28.2gr was 2525 fps. Little slower than I expected but the barrel is brand new and it was about 50°f. Lever is temp sensitive as I have done temp testing using my 6.5 Grendel and it was 1.4 fps for every degree of temp. 

As far as velocity I was hoping to get about 2650?  I can go up another .2 grains according to Hornady's data for a 100gr projectile. I'm running 2.14 COAL, which is about 20 thousands off the lands.  My grandson shot a 1.5" group at 100 yards so I was happy with that but the velocity was not as good as I was expecting. For velocity comparisons, out my 18" AR 6.5 Grendel I could push a 100 grain AMAX over 2700 fps.

Deep winter up here in Northern Michigan am am looking seriously at this cartridge for a bolt gun and possibly a barrel/bolt for a currently chambered .223 Rock River AR.  I handload and am interested in precision shooting out to 500 yards.  I have hunting calibers very well covered.  I hope to learn a lot here and have the itch for another cartridge to experiment with.
I have an Otter Creek Polonium K that covers .223/6mm that I'd like to use on a build.

Found a site selling Hornady 110 Gr A-Tips at not stupid expensive prices, just had to wait a month or so to get them.

Using their reloading app, and knowing what I had available, loaded up 50 rounds, 25 each with Leverevolution and H4895, with 5 shot groups at 100 yards.

Forgot to include barrel length in my edited photos, at 26 inches.  All other rifle/load data is in the pics.

I think I'll be ordering more of these bullets, if I can get them at similar prices.  From what I had today, I'll likely be loading H4895 at 26.4 grains, using a powder throw instead of auto dispenser.

   

   

Finally got some time to run the 6ARC using 103 ELDX and 90 ELDX.  Top 8 are 103 and bottom 4 are 90.  All 5 shot groups at 100 yds portable bench at my in wood range protected from most wind.  Temps around 32f.  I had a little mirage and eye watering to deal with, but seems when I was patient enough to wait a bit things cleared.  Using my Leupold VXIII 4.5-14. I prefer a little better glass for my load development, but this one was handy.  I also prefer a distinct + to help align the crosshairs so I altered my targets for next session. 

First group looks decent unfortunately not zero'd quite right.  I plan to explore the next steps higher on the 103 to see if the SD comes down.  My 90 gr go-to loads are not shown here.  I went where QL told me to go and put the other loads on a different target.  They picked up speed and higher SD with the suppressor so I am slowing them down a bit. 


Gun is Cobalt Kinetics AR 15 SPR Elite with 22" Proof carbon barrel.  I'm impressed, especially for a semi auto.  

Powder used is LVR.  Charge weights approaching or exceeding max on the 103. 


           

I've been building AR-15s in 5.56mm and .300BLK for a few years now and am planning to build a 6mmARC upper.  I have an Aero upper receiver and M-Lock handguard and a Ballistic Advantage 18" 1-7 rifle length SPR premium barrel for this.  I plan to use it with either one of my match rifle receivers or possibly a carbine built on a Spikes Tactical receiver.  

My AR-15 uppers (10.5" to 20" barrels) are interchangeable and work well with all of my lowers.  Is there any problem with just dropping a 6mmARC upper into various lowers that all work well with 5.56mm?

Thanks in advance for any helpful hints before I get started?

`Long story short. I am looking into picking up a 16 inch arc barrel from roscoe with a rifle gas system. It seems pretty new so i am curious if anyone here has used it and any feedback or advice for it. 


The build will be a replacement for my current patrol rifle, and plan to use the A5 buffer system from BCM, maybe a Kynshot buffer (havent seen if they make an A5 yet). Geissele MK16 rail, and tricon trigger, probably a BCM upper, and a new frontier lower (i know, cheap, but it is one i designed). 

I am sure i will need an adjustable gas block, or light weight BCG. but that is the whole point of me coming here, to get feedback. 

thanks in advance.

Finally, finally, FINALLY our Rexus UltraBolts and Rexus Ultra Bolt Carrier Groups are back in stock.

Shipment arrived Christmas Eve and we think Santa did us a Christmas Miracle cuz he loves AR15s!

Find them at REXUS OUTFITTERS.

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Christmas was good this year     

Anyone care to share any experiences with the 80 grain ELD-VT bullets.