Midway has the CMMG upper in stock and on sale for $459. ($240 off)
I absolutely love the one I put on my M&P lower!
The 1st group I shot using the Hornady Black 105gr was under 0.5”. (Edit to add: more like 0.35”) After barrel break-in, nothing has changed.
It also shoots the ELD-VT 80gr load very, very well. Haven’t started reloading for it yet, still making empty brass.
This is my first M-Lok forend and I’m getting spoiled by the slim feel.

6mm ARC Upper

This message has been edited. Last edited by: KMitch200,

Thanks for the notice, KMitch200.

Would you fill in details on your accuracy testing, please?

Shooting was done off bench, 100 yds.
I pulled my scope off of my 308 AR because I didn’t have another cantilever mount. Didn’t bother to bore sight, it was just going to be a barrel break in day. I took aim at a spot on the berm and it hit really close to POA. Aimed at a 2” dirt clod and hit it.
Moved to paper and the 4 shot group (the 1st on paper) was one hole - 1moa down, 1moa right.
Adjusted the scope accordingly and the next 5 shot group was right at 0.5” centered.

Cleaned, shot the ELD-X and it was about 1.5” - same with the ELD-M.
(I am going to try those again on a cooler day.)
The ELD-VT was a nice group IIRC 0.75” but I was having an issue with one of the Stoner mags.
(Returned for replacement, no issues now)

I’ll get out again when it’s below 90°.

I don't see it mentioned, but I must ask if it has an adjustable gas block?

No adjustable gas block…yet.
That’s further down the road for now.

Thanks.
After my one experience with an adjustable block, I like the idea of something that works without having to fiddle with it. I know that may not be feasible with all loads, but I'm willing to stay withing a reasonable range.

Again.


https://www.midwayusa.com/prod...025972159?pid=950586

That's a good price for quality upper. Hornady did a nice job with the 6 ARC cartridge, although it's not much different than a 6 Grendel.

I have a 24" barrel 223 AR15, with a barrel that's very close to being retired. 6 ARC was a strong option, but I ultimately bought a 20" Wylde replacement barrel. I will likely switch out the barrels early next year.

Wilson Combat has a sale going on, with 6 ARC components at an attractive price. Yet again I ran the ballistics figures before ordering parts. I have a few options for AR15 rifles/uppers, so in order to justify a new caliber, it had to do something noticeably better than my current uppers. I was looking at their 18" barrel.

I don't hunt small/medium game, so the 6mm bullet doesn't offer either a practical or legal advantage over a 223 bullet. The varmints that my attention are easily handled with 223.

I have plenty of SD/HD firearms options, so the 6mm bullet doesn't offer a big advantage.

I again reviewed the rules for AR15 and 2-rifle matches in my region. All the ones I'm interested in require that the AR15 be chambered in 223/5.56. Therefore, I can't use the better Ballistic Coefficients of the 6mm bullets in competition.

And thus it comes down to training & practice -- how does the 6 ARC stack up against my existing rifles. My best AR15 rifle is an SI Defense receiver set with a 20" Krieger barrel. Preferred ammo is Hornady 75 HPBT Black, with an MV of 2784 fps. Based on web reports, I suspect a reasonable MV for Hornady 6 ARC 108 ELDM in an 18" is 2540 fps. The JBM ballistics data at my altitude:
223
- 500 yards @ 9.6 MOA drop, 3.7 MOA drift with 10mph crosswind
- 600 yards @ 13.3 MOA drop, 4.6 MOA drift
6 ARC
- 500 yards @ 10.8 MOA drop, 2.8 MOA drift
- 600 yards @ 14.5 MOA drop, 3.4 MOA drift

At 500 yards the 223 has 6 inches less drop and 5 inches more drift.
At 600 yards the 223 has 8 inches less drop and 7 inches more drift.

Bottom line -- I don't see enough difference to add a caliber. And I even have a spare scope & mount sitting in the basement, so there's no cost there.

I think 6 ARC will work for many shooters, but for now, I'm not buying in.