I'd say Benchmark, h322, and xbr for that weight range. 3350-3450 fps with 58 grain vmax in a 20".
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But honestly the 6 arc is as you say designed for heavier bullets and really shines at the 87 vmax and heavier. Because of the reduction in suggested operating pressure in 6 arc you loose some of the potential of the cartridge that isn't made back up until you maximize the bc with the improved geometry of the shorter case in an ar15 platform.
A 223 wylde or 556 nato chambered ar15 can send a 53 vmax or 55 blitz king out at north of 3400 fps in a 20 inch barrel.
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A light 6 arc has nearly identical trajectory and energy to a 53-55 grain in a 556 nato capable ar 15 with the same barrel length. I don't think the difference is worth it.
Any real analysis of the 6MM ARC in an AR 15 leads you to what I call a one trick pony rifle cartridge combination conclusion. This happens to be why I got one, it does 1 thing really well. However it's really a 3 trick pony.
In an AR with light weight projectiles a standard chamber does not fair well. If you cut a custom chamber you give up the one thing the 6MM ARC does do well.
With heavy projectiles (105 or 108) at 52,000 PSI, the ARC is flatter, has significantly more energy and is 70% better in the wind at any range than anything from a 5.56 in a 20" barrel. That includes any match projectiles 69 to 75 grain.
Stag Arms wind test shooting both simultaneously showed at 800 yards the 75 grain 5.56 actually drifted 62" while the 105 6MM drifted 30" The 5.56 just runs out of gas with the heavies even from the 20" A2. I tested my AR 15 A2 and anything over 69 grains is a ballistic disadvantage in my Colt.
The 6MM ARC with the 108 is flatter and is significantly better than the 7.62x51 NATO with 175 grain match projectiles in the wind. The 7.62 still has more energy at 1,000 yards but loses significantly in the other 2 categories.
The 2nd trick it does is CQB, it is extremely good in close, my rifles felt recoil is less than an M4 and combine that with the reach and you have what may be the AR 15 in 6MM ARC 3rd trick.
It's a great general purpose truck, Jeep, horseback, farm, general family defense and medium game hunting rifle cartridge combination, it's why I have one. It's a great tool!
It's not my varmint rifle, I have a bolt 223 and 6MM Remington, it's not my elk rifle, I have 3 or 4 others better suited, it's not my dangerous game rifle, I have a specialty rifle for that. If I shot matches it would not be my match rifle.
If I'm working in the field or the situation get sporty, then it's my rifle.