CMMG 6MM ARC Endeavor 300 MK 4 Review. The video is long… TLDR/Watch; Star rating, 3.5/5
Specs to the rifle from CMMG:
Specs for the optic (EBR-7C FFP):
Badger Ordnance mount:
I took the rifle to the range for a couple of trips. First trip was shooting steel out to 600 yards. Hits on steel were 100% until I got to 600. At that point, my hits were about 50%. I honestly expected to do better with this loading. Later, I made another trip to shoot for groups. When I shot the groups, I discovered why my hits at 600 we’re not landing reliably. It turned out the rifle shoots about 1.5 MOA, with my steel target at 600 being slightly smaller than that, there’s really nothing I could do but hope my shots hit.
Overall, the accuracy of the rifle is acceptable, but also a little disappointing. I expected more, but not all is lost… I have a plan to address the accuracy “issues”. This is explained in the video. Overall, an AR 15 style rifle that shoots 1.5 MOA is “good”, so I shouldn’t complain. I’ve only been able to run about 60 rounds through the rifle, but it was 100% reliable with the 10 round mag. I didn’t have a chance to try out other magazines. I don’t see a reason not to recommend this rifle, but I suggest looking at other available options, and I would not pay more than the manufacturer’s suggested price. That goes for any firearms being sold.
It's a beauty! Be proud, good luck finding one now.
I have Faxon 12" , Brownells 16" and BA 18" 6ARC . I'm getting the best and most consistent accuracy with Black 105g BTHP. My 12" is Gunnee Profile so not heavy at all . I'm getting 0.91 MOA for 3 shot group . Getting about 2.2 MOA once barrel heats up . With my 18" it's a super Heavy Profile . I'm getting 1.6 MOA with 10 shot group . I've taken this out to 600 yards. I hit torso Sized steel target 5x in a row with Black 105g BTHP.
The 16" Brownells has been the most inconsistent. One day its 1 moa the next day it 2 moa . It's not the best barrel in the world for accuracy but it will get the job done .
Co worker has 16" Proof SS Barrel and he us getting very good accuracy and Velocity. Proof Barrels so far has the been the best barrel I've seen so far .
6mm ARC IMO is the best AR15 CARTRIDGE. The 6arc and 6.5g are true do all be all cartridges for AR15 . 6ARC would be a lot more popular if it wasn't for CV . I'm lucky I bought all my ammo when it was still under 1.50 a round .
Hornady states a 24" Bolt Gun will get 2750 FPS with Match or Black and 2800 FPS with 103g ELDX.
They also state with 18" Proof gas Gun barrel you'll get 2625 FPS . Which is almost on point and not too far off . I'm getting 2600 with my 18" BA .
I'm getting 2400 FPS with my 12" and 2540 FPS with 16" .
The 12" is my do all be all AR15 Pistol . It blows me away every time I shoot it . 600 yards and in for 12" was my primary goal and it hasn't disappointed..
I didnt really shoot for groups until 80 to 100 rounds fires through
I've fallen in love with 6mm ARC
Order a bolt action upper from Uintah Precision. Fits right on your lower, Problem solved.
How do you like the scope position? Seems to be pretty far back. The ammo is definitely way too expensive right now. A ton of the stores are selling the ammo on auction sites instead of offering it to their customers. That way they can get more money, while not being seen to price gouge.
6mm ARC is not same as necked down 6.5 Grendel. I believe the case shoulder geometry differs also.
Today, I got the barrel nut wrench, and when I removed the barrel nut, I noticed the fit between the barrel extension and the receiver is extremely loose. I shimmed it and set it up with green Loctite. I also re-torqued the barrel nut to a lower torque setting. When I was trying to see what the barrel nut was originally torqued at, I stopped trying when my torque wrench went above 50 foot pounds. There’s no need to torque the barrel nut that high since you don’t have to index for the gas tube with the MWI barrel nut. I set it at 50 foot pounds. Tomorrow, I’ll take it out and see if the accuracy has improved.
Edit: Accuracy with the 108 grain improved, but better is that all the groups were at a consistent point of impact, and overlapping all the groups, all shots would’ve fallen within 1.5 MOA. Average group size went down to .93
if you try a suppressor it may help to improve the barrel harmony