6mm ARC vs 6x45

[SD guy]

While I have no personal experience with the 6x45 I have been intrigued by the idea of this chambering in a mini action rifle like a Howa or CZ 527.
The 6ppc also intrigued me though, in a fast twist for 100 grain bullets perhaps heavier. For reasons I did not understand I was told essentially PPC & fast twist were not a good match.

Then the 6mm ARC came out & The best commercialized option of all for a mini action 6mm rifle was now becoming more readily available. Two years ago I ordered a 22" barrel for a CZ527 & have been quite satisfied. Biggest issue has been an ongoing struggle to find brass.
So far the Brass is more challenging & or expensive, perhaps more work than most would prefer. Converting 6.5mm Grendel Lapua & now Starling have been my favorite choices due to price & availability. Now Lapua offerings have been discontinues at least for the time being. There has been talk of hornady ramping up production & Starline offering an actual 6mm ARC head stamp option before long. Who knows how long till the bottleneck in options for 6mm ARC brass may be resolved.

See talk on the 6x45 again & honestly I can see the appeal. Primary advantage of the 6x45 over the 6mm Arc currently is brass availability IMHO. For those wishing to build a rifle, The availability of a wide choice of actions could be appealing as well I suppose.

Personally I hav acquired enough Grendel brass that the 6x45 has almost completely fallen from consideration for me. Though I can see where the appeal of the 6x45 may be quite strong in our current supply situation. Really have been pleased with the 6mm ARC as a low recoil powder miser of a deer rifle that has not given up much in terms of terminal performance when compared to the bigger 6mm offerings.

Interested in opinions out there in what the 6mm Arc does better than the 6x45 as I have no hands on time with the 6x45. Recently looked at ordering another barrel & considered the 6x45, though decided I have all I need for 6mm ARC now, such as dies & brass. So 6mm ARC won out for me.

What would be the case for those just starting out today with no dies or brass? I can see where the 6x45 may look more attractive.

 

[jelenko]

I think it would depend on what you're wanting to do.
I assume there is a big difference in external ballistics between 6x45 and 6ARC.

 

[David Milisock]

The 5 grain of water less capacity of the 6x45 puts into question the usefulness of the cartridge. The 6MM ARC to me seems as slow as I'd want to go in an AR.

 

[AWS]

If you want to lob heavies more horsepower is always going to be better.

I have had a 6x45 for thirty years and built a 6mm-204(think 6x45AI+), still shooting the 6x45 and the 6mm-204 is back in the barrel rack if I find a reason to reactivate it. The 6x45 is very accurate as was the 6mm-204 they both kill coyote with authority so two 6s weren't needed and so the 6mm-204 became a 20P.

 

[SD guy]

AWS, What barrel twist did you go with on your 6x45?

While I expected a greater sacrifice in velocity. Based on Hodgdon load data that I have looked at we are not really giving much if our use is inside of 200 yards. Giving up 150 fps or so over the ARC. Expect the 105's - 115's may be quite impractical though.

 

[swd]

For me it would depend on what action I have available and or brass supply. If you already have a 223 or a PPC bolt face action then that would make the choice either way for me. And then there’s the 6BR option if you a .473” bolt face action.

And then of course there’s application. The 6x45 is pretty solid to 600ish yards with a 95SMK after that heavier bullets with more oomph behind them from a larger case have a definite advantage..

 

[Raptor]

I honestly think the 6ARC will walk all over the 6x45 esp using one in a bolt gun. They are both very accurate but the ARC has all the advantages that make it a better round, esp in a bolt gun.....

 

[HandgunHTR]

I honestly think the 6ARC will walk all over the 6x45 esp using one in a bolt gun. They are both very accurate but the ARC has all the advantages that make it a better round, esp in a bolt gun.....

I don't know if I would say "walk all over". An extra 100 fps doesn't get you a whole lot until you get over 600 yards. How many people are shooting that far?

 

[DiRTY DOG]

Depends on the bullets you intend to use. Reports I've seen show fast twist 6mmARC barrels are a poor choice for lighter bullets for example fast and flat shooting 55-70gr varmint type bullets. The 6mmARC is designed for heavy bullets and the extra case capacity sure helps.

 

[JB10]

I built a 6x45 but testing bullets from 55 to 70gr only. Im not hunting deer with it. Varmint and predators is what i wanted it for. My decision was easy with 5 five gallon buckets of 223 brass sitting around

 

[CaptJim]

Year before last I built a 6X45 AR with an 18" 12 twist X-Caliber barrel and this year I built a 9 twist 14". Haven't had time yet to even break the 14" in. These will be primarily for varmints/target but the 9 twist should shoot an 85 gr Gameking fast enough for Whitetail deer at a reasonable distance. The 12 twist seems to like 65 gr V-Max the best so far, but haven't shot it but maybe 50 rounds so far. I will post back as I collect some data.
CJ

 

[JSH]

Put a 6TCU rifle together right before they let the 6ARC out. If I had known I would have went with the 6ARC. The two are so close, not enough to argue over a cup of coffee.
The 6ARC has the advantage of NEW data for NEW powders, not reprinted 20-30 year old data with powders of that era and no others.
The PPC put the 223 and 222 mag case out of the BR game a long time ago.
Yes I can and have played with some new powders for the 6TCU. I have burned up a fair bit of time working with some new powders, some show promise others not so much. Up to date 2000’s data would be nice, but imagine not cost effective.

Buckets of 223 brass, some what of a poor excuse. I seldom use used brass when fooling with a wildcat. Used brass just adds another variable I don’t need.

 

[SD guy]

Depends on the bullets you intend to use. Reports I've seen show fast twist 6mmARC barrels are a poor choice for lighter bullets for example fast and flat shooting 55-70gr varmint type bullets. The 6mmARC is designed for heavy bullets and the extra case capacity sure helps.

Would like to see the data that proved fast twist 6mm ARC barrel is not doing well with lighter bullets. Granted the 6mm Arc is optimized for heavier / longer bullets in terms of twist rate. Though in my experience The Arc does well with the light stuff also.

Lightest bulletsI have tried in the 6mm ARC have been 55 grain Hammers.

 

[DiRTY DOG]

Would like to see the data that proved fast twist 6mm ARC barrel is not doing well with lighter bullets. Granted the 6mm Arc is optimized for heavier / longer bullets in terms of twist rate. Though in my experience The Arc does well with the light stuff also.

Lightest bulletsI have tried in the 6mm ARC have been 55 grain Hammers.

To be fair, copper bullets like the 55gr Hammer are longer than lead bullets of the same weight, a 55gr copper is roughly the length of a 70gr lead bullet.

How come nobody ever talks about using 55gr NBT or 58gr Vmax in 6mm ARC? Maybe there's a reason?

 

[muleystalker]

If you want to lob heavies more horsepower is always going to be better.

I have had a 6x45 for thirty years and built a 6mm-204(think 6x45AI+), still shooting the 6x45 and the 6mm-204 is back in the barrel rack if I find a reason to reactivate it. The 6x45 is very accurate as was the 6mm-204 they both kill coyote with authority so two 6s weren't needed and so the 6mm-204 became a 20P.

Actually the the 6x204 is more like a 6x47 Improved (6x47=6x222mag) than a 6x45AI.The 6x47 not to be confused with the 6x47Lapua. The .204 case is like an improved 222mag.

 

[SD guy]

To be fair, copper bullets like the 55gr Hammer are longer than lead bullets of the same weight, a 55gr copper is roughly the length of a 70gr lead bullet.

How come nobody ever talks about using 55gr NBT or 58gr Vmax in 6mm ARC? Maybe there's a reason?

Perhaps folks shooting the 6mm arc Just do not care for the idea of shooting projectiles with the BC of an ashtray. Thus few if any have given them a try.

 

[swd]

I think the magic of the 6x45 is it works on any 223 action, the ARC doesn’t.

 

[David Milisock]

To be fair, copper bullets like the 55gr Hammer are longer than lead bullets of the same weight, a 55gr copper is roughly the length of a 70gr lead bullet.

How come nobody ever talks about using 55gr NBT or 58gr Vmax in 6mm ARC? Maybe there's a reason?

I've been shooting the 6MM Remington for varmints for decades. I've shot 243, 6x47, 6-284, 6-06 and 240 Weatherby, possibly some othfor.
I just got into the 6MM ARC and I'm impressed with its ability to do what it was designed for.

I've never did anything other than testing with subb75 grain 6MM projectiles, I could never make them work.

 

[SD guy]

I've been shooting the 6MM Remington for varmints for decades. I've shot 243, 6x47, 6-284, 6-06 and 240 Weatherby, possibly some othfor.
I just got into the 6MM ARC and I'm impressed with its ability to do what it was designed for.

I've never did anything other than testing with subb75 grain 6MM projectiles, I could never make them work.

Mind if i ask if your 6mm ARC experience has been with a gas, or bolt action rifle?

 

[AWS]

SD guy, both my 6x45 and 6mm-204 have 1-10 twist barrels.