6mm ARC in AR platform Loading Advice?

[Steve Donlon]

I wanted to change to a digital scale for the 6ARC loads because of the lack of head room on max pressure compared to my other gas guns and my bolts.

With a balance beam the angle of viewing the scale is critical and I don't need a 1 to 2/10th error in charge weight. In my opinion the 6ARC in an AR needs to be loaded very near the 52,000 PSI max. In a 16" barrel I'm only going after 2,550 FPS which is very near WHT factory rounds clock in my rifle. This makes the 6ARC trajectory about the same as my 20" A2 in 5.56 with match grade projectiles but the 6ARC is a better than 60% improvement in wind and twice the energy at max effective 5.56 ranges and continues to be effective for a few more hundred yards.

With your 6mm Remington you are covered as long as they are accurate and safe, that's my goal anyway. Accuracy is always better than velocity as many have said. That's why we are here.

 

[David Milisock]

With your 6mm Remington you are covered as long as they are accurate and safe, that's my goal anyway. Accuracy is always better than velocity as many have said. That's why we are here.

What is accuracy? Is it the best group? Is it 1 shot hitting closest to the point of aim and a great group? Is it 1 shot hitting at point of aim but 4 more producing a ho-hum group.
I shoot at ranges to work loads, I average groups particularly under adverse conditions, hot and cold as I can get, calm and windy. I practice field positions, acquiring and firing as fast as possible, within 5 seconds is my goal.

My 2 varmint rifles a 223 in a Howa 1500 varmint kit rifle and a 6MM Remington in a 700 Remington BDL varmint. Both rifles will chime in on average at 1 1/16" groups at 300 yards.

Is that the best groups that these rifles can do? No! I can get both rifles down to 1" at 300 yards, the 223 only in semi-rare light wind conditions.

However the velocities in both rifles that produce the best groups produce unacceptable trajectories and wind resistance for field work and the best groups on average are only 1/16" better. In respect to the 2 1/2" target area of a chuck or a crow the question is how relevant is that 1/16"?

The groups that I use produce with the higher velocity loads produce the ability to place a round on target in a wider set of variables. Especially the 223, a extremely faster 40 grain, (3,900 FPS) handles wind and shoots much flatter out to 350 yards better than heavier weight projectiles in my rifle.

Similar can be said about my 6MM Remington but the range increases to 500+ yards. I shoot 3,900 FPS with a 75 grain VMAX, within the effective range heavier projectiles make hits harder in the field.

Same process can be handled for medium game, pig, deer, elk, except the target area is 4". I would argue that velocities value need be weighed even heavier than an additional 1/16" group improvement as in this vcase energy/knock down value on target is far more critical with larger game.

 

[Steve Donlon]

What is accuracy? Is it the best group? Is it 1 shot hitting closest to the point of aim and a great group? Is it 1 shot hitting at point of aim but 4 more producing a ho-hum group.
I shoot at ranges to work loads, I average groups particularly under adverse conditions, hot and cold as I can get, calm and windy. I practice field positions, acquiring and firing as fast as possible, within 5 seconds is my goal.

My 2 varmint rifles a 223 in a Howa 1500 varmint kit rifle and a 6MM Remington in a 700 Remington BDL varmint. Both rifles will chime in on average at 1 1/16" groups at 300 yards.

Is that the best groups that these rifles can do? No! I can get both rifles down to 1" at 300 yards, the 223 only in semi-rare light wind conditions.

However the velocities in both rifles that produce the best groups produce unacceptable trajectories and wind resistance for field work and the best groups on average are only 1/16" better. In respect to the 2 1/2" target area of a chuck or a crow the question is how relevant is that 1/16"?

The groups that I use produce with the higher velocity loads produce the ability to place a round on target in a wider set of variables. Especially the 223, a extremely faster 40 grain, (3,900 FPS) handles wind and shoots much flatter out to 350 yards better than heavier weight projectiles in my rifle.

Similar can be said about my 6MM Remington but the range increases to 500+ yards. I shoot 3,900 FPS with a 75 grain VMAX, within the effective range heavier projectiles make hits harder in the field.

Same process can be handled for medium game, pig, deer, elk, except the target area is 4". I would argue that velocities value need be weighed even heavier than an additional 1/16" group improvement as in this vcase energy/knock down value on target is far more critical with larger game.

Well, every week we shoot at 300, 500, 800 and 1000 yards with 30-06 and 6.5 creedmoor. Hear at 7000' feet in the mountains the wind is always relevant. At longer distances it will be coming from different directions at the same time. It's a challenge for fast follow up shots with the 30-06. My friend reads the wind better than I do. I'm impatient. I really respect reading the wind. Accuracy for me is less than one MOA under all conditions. A 2 1/2" group at 800 yards is just a bonus on a beautiful day with no wind at sunrise. AR 223 out to 500 maybe 800 in a steady light wind. 300 BLK , 300 yards under all conditions. AS for bullets, the heaviest ones that work to meet my goals. I hope that explains where I'm coming from amigo.

 

[David Milisock]

Well, every week we shoot at 300, 500, 800 and 1000 yards with 30-06 and 6.5 creedmoor. Hear at 7000' feet in the mountains the wind is always relevant. At longer distances it will be coming from different directions at the same time. It's a challenge for fast follow up shots with the 30-06. My friend reads the wind better than I do. I'm impatient. I really respect reading the wind. Accuracy for me is less than one MOA under all conditions. A 2 1/2" group at 800 yards is just a bonus on a beautiful day with no wind at sunrise. AR 223 out to 500 maybe 800 in a steady light wind. 300 BLK , 300 yards under all conditions. AS for bullets, the heaviest ones that work to meet my goals. I hope that explains where I'm coming from amigo.

I get it, I use what I use because 99% of my field work is under 500 yards shooting at small things. Yes I do occasionally shoot farther and at larger targets but not much, lately testing my AR in 6MM ARC with 103's and 105's had me doing this. BTW a great general purpose cartridge rifle combination, not great at any one thing but good at alot of things.

I'll get into an area, many times a terraced farm field with a multitude of wind directions and velocities, I range land markers, I'll know marker A is 165 and marker B is 325, the chucks don't hang around long, being zeroed at 300 and having my trajectory plotted, I dope the wind and based on a rough range estimate hold over or under, if the bugger hangs around long enough. Of course if there's enough time I'll note as many markers as possible, at my age I make a note. In this situation the 223 works reasonably well unless the wind gusts up, then the 6MM is my go to.

That's where the hyper velocities pay off, the small arc in the trajectory and reduced time of flight. In both rifles the difference between 1" groups at 300 and 1 1/16" is 500 to 600 FPS.

Now the bite is even with the 6MM Remington out past 500 the bullet choice is poor, also with my pressures barrel life is short and that means no dog towns.

BTW I thought about a 6,5 Creedmoor but I have a decent Swede and my thoughts stopped there.

 

[CKAB]

Did you find a good load yet ? i have an APF 6ARC with a 18" Carbon barrel and it likes 29.3 Lever with a 105 at mag length