6mm ARC

[L2bravo]

Is anybody running one in a bolt gun? Was looking at resizing 6.5 Grendel to the 6 ARC.

What powders? What bullets? What speeds?

How will this compare to a 6br? Will enjoy the same brass and barrel life? Easy to tune?

As always, if you have pictures post them up.

Thanks in advance guys.

 

[cro789]

Just got mine and haven’t had the time to start load development yet but from the testing with factory ammo looks very promising. Sub 1/2. Will be running Berger 105 with varget and Lapua b6.5 brass necked down. As soon as I get home I will try to start the process.

 

[Ledzep]

I've been shooting it for about 2 years now. It's an ARC Nucleus, 28" Bartlein 7.5" twist no contour 1.25" pipe.

Velocity with varget max book load (28gr) is ~2750fps give or take. Velocity with factory ammo (Hornady 108) is in the 2810-2830fps range. With LeverEvolution or CFE223 max book loads you can push 108's or 110's in the upper 2800's to low 2900's. Ultimately I ended up running Varget for temp stability, slightly better precision, and because the lower velocity means practically no recoil from the 20lb rifle. The ballistic difference between 2900 and 2750 is negligible (wind error difference, range error, etc.. is all within .1 mil within PRS/NRL ranges). Pretty comparable overall to a BR, maybe a touch slower using the same powder.

I have 3800 rounds on this barrel and it's still shooting pretty much the same as when it was new. 2750fps with the varget load, and 20 shot groups in the 1.3-1.6" range at 200yd. At every round count that I've looked with a bore scope, it looks like a 6.5 Creedmoor that has about half as many rounds on it. By 3000 I started getting some fire cracking, and now it's visible to the naked eye from the rear. I may be edging in on the end, but even so 4000-5000 rounds is no slouch.

You can size down grendel cases but honestly I'd just track down some factory ammo or 6 ARC cases. I've mixed in some range pick-up grendels with my ARC brass and accidentally sized them and, despite feeling totally wrong when running the press, they've all sized down fine. Can't guarantee you won't wreck some shoulders, though. Just seems like a lot of work that I would rather pay for new cases, but that's a personal decision.

 

[L2bravo]

I've been shooting it for about 2 years now. It's an ARC Nucleus, 28" Bartlein 7.5" twist no contour 1.25" pipe.

Velocity with varget max book load (28gr) is ~2750fps give or take. Velocity with factory ammo (Hornady 108) is in the 2810-2830fps range. With LeverEvolution or CFE223 max book loads you can push 108's or 110's in the upper 2800's to low 2900's. Ultimately I ended up running Varget for temp stability, slightly better precision, and because the lower velocity means practically no recoil from the 20lb rifle. The ballistic difference between 2900 and 2750 is negligible (wind error difference, range error, etc.. is all within .1 mil within PRS/NRL ranges). Pretty comparable overall to a BR, maybe a touch slower using the same powder.

I have 3800 rounds on this barrel and it's still shooting pretty much the same as when it was new. 2750fps with the varget load, and 20 shot groups in the 1.3-1.6" range at 200yd. At every round count that I've looked with a bore scope, it looks like a 6.5 Creedmoor that has about half as many rounds on it. By 3000 I started getting some fire cracking, and now it's visible to the naked eye from the rear. I may be edging in on the end, but even so 4000-5000 rounds is no slouch.

You can size down grendel cases but honestly I'd just track down some factory ammo or 6 ARC cases. I've mixed in some range pick-up grendels with my ARC brass and accidentally sized them and, despite feeling totally wrong when running the press, they've all sized down fine. Can't guarantee you won't wreck some shoulders, though. Just seems like a lot of work that I would rather pay for new cases, but that's a personal decision.

Wow. That’s a lot of data. I think I’m headed into the BRA, but I may still get a barrel at some point. But this seems really similar. How far have you shot it? 20 round strings, 1.3” @ 200, is strong.

 

[Ledzep]

It's pretty solid to 1000, maybe a little more. Like any of the small 6's it starts really losing steam by 1200. I've hit the far targets in most of the PRS or NRL matches I've been to, which most are in the 1000-1250yd ballpark. If they didn't have magnetospeed indicators, though, most of the time nobody at the firing line would know it "Just enough" to get there.

 

[kthomas]

Wow. That’s a lot of data. I think I’m headed into the BRA, but I may still get a barrel at some point. But this seems really similar. How far have you shot it? 20 round strings, 1.3” @ 200, is strong.

The BRA is an excellent cartridge.

I don't see what the advantage of a 6ARC is over a BR variant in a bolt gun.

 

[ormandj]

The BRA is an excellent cartridge.

I don't see what the advantage of a 6ARC is over a BR variant in a bolt gun.

Non-Lapua factory ammunition. Don't discount it; for some people, it's a big plus.

 

[Franko]

The BRA is an excellent cartridge.

I don't see what the advantage of a 6ARC is over a BR variant in a bolt gun.

From my experience the 6BR only feeds well from a magazine (with a kit) when its loaded with long for caliber bullets (Sierra 107, Berger 105, etc.).

If a 6ARC will feed ammunition loaded with light and heavy bullets from a magazine and shoot it accurately; I would consider replacing my current 6BR with one. After all, I reload so why shouldn't I be able to get as much versatility as possible out of any cartridge I am reloading?

 

[JCARL]

I've been shooting it for about 2 years now. It's an ARC Nucleus, 28" Bartlein 7.5" twist no contour 1.25" pipe.

Velocity with varget max book load (28gr) is ~2750fps give or take. Velocity with factory ammo (Hornady 108) is in the 2810-2830fps range. With LeverEvolution or CFE223 max book loads you can push 108's or 110's in the upper 2800's to low 2900's. Ultimately I ended up running Varget for temp stability, slightly better precision, and because the lower velocity means practically no recoil from the 20lb rifle. The ballistic difference between 2900 and 2750 is negligible (wind error difference, range error, etc.. is all within .1 mil within PRS/NRL ranges). Pretty comparable overall to a BR, maybe a touch slower using the same powder.

I have 3800 rounds on this barrel and it's still shooting pretty much the same as when it was new. 2750fps with the varget load, and 20 shot groups in the 1.3-1.6" range at 200yd. At every round count that I've looked with a bore scope, it looks like a 6.5 Creedmoor that has about half as many rounds on it. By 3000 I started getting some fire cracking, and now it's visible to the naked eye from the rear. I may be edging in on the end, but even so 4000-5000 rounds is no slouch.

You can size down grendel cases but honestly I'd just track down some factory ammo or 6 ARC cases. I've mixed in some range pick-up grendels with my ARC brass and accidentally sized them and, despite feeling totally wrong when running the press, they've all sized down fine. Can't guarantee you won't wreck some shoulders, though. Just seems like a lot of work that I would rather pay for new cases, but that's a personal decision.

What do factory 108's do out of that long tube?

 

[trdjohn]

What do factory 108's do out of that long tube?

I've got a 26" McGowan on Origin SA, factory hornady 108 eldm ammo average 2,742 fps / SD 11 in mid 30 deg temps

 

[JCARL]

I've got a 26" McGowan on Origin SA, factory hornady 108 eldm ammo average 2,742 fps / SD 11 in mid 30 deg temps

Ok, thanks. Faster than I thought.

18" BA 6arc shoots 108 factory right at 2600.

Proof 6BR went from 2890 at 26" w/ 108's & 29.5gr H4895 to 2840 @ 22".

Seemed that the old standard 25fps/inch of barrel length estimation was optimistic with lower case capacity rounds.

 

[trdjohn]

Ok, thanks. Faster than I thought.

18" BA 6arc shoots 108 factory right at 2600.

Proof 6BR went from 2890 at 26" w/ 108's & 29.5gr H4895 to 2840 @ 22".

Seemed that the old standard 25fps/inch of barrel length estimation was optimistic with lower case capacity rounds.

So hand loads - top end 30.2 gr of Lever in 70 deg that averaged 2,835 fps, SD 9.3 from the 26" barrel. With insensitive powders, top end dose of H4895 (27.2) it averaged 2,754 and IMR 8208 (26.2) it averaged 2,676 fps in upper 30s F - those were in the fall and early Dec - and less than 200 rounds thru the barrel - winter got in the way here and other things too - will start shooting it more in a the coming weeks - we'll see where it stands after a few hundred more

 

[Spikediesel]

I've got a 26" McGowan on Origin SA, factory hornady 108 eldm ammo average 2,742 fps / SD 11 in mid 30 deg temps

I saw the same results today with 108 Eldm and a 26” proof. Ammo fed flawlessly with the MDT 6ARC mag. Can’t wait to go out next time with these 95g Bergers!

 

[Spikediesel]

Today was finally load testing day for my 6 Arc.

Rifle:
Zermatt Origin
26” Proof competition
XLR Element 4.0
Triggertech Special 2 stage
Bushnell DMR 3
EC tuner brake

Ammo:
95g Berger target VLD
Federal 205m primer
Hornady brass
Lever evolution powder

Using Hornady’s guidance for bolt gun pressures my goal of 3000fps was easily achieved. I was incredibly happy with the results, and accuracy was phenomenal! In my opinion a bolt gun really brings this cartridge to life and makes it downright impressive! I think my load that yielded 2950fps will be my go to as it was easier on the brass and had the lowest SD/ES. Strelok shows this load only drops 9.11 mils at 1000yds, that matches my factory 140eldm load in my 6.5 creed!

 

[L2bravo]

That is badass.

 

[evilsvt]

22” proof on a TL3 shooting 55gr Hammer Hunters at 3550 with an ES of 6.