6 ARC

[Retired shooter]

Hello All
Another guy seriously considering a new upper for my AR in 6ARC. Had thought about 224 Valkrie. Doing lots of research, finding out about blown primer pockets. Looks to be some having bolt lug breakage in 6 ARC. Anyone care to share current information.

Equipment malfunctions, possible human error, both. Would like some imput before we go any further.
Sorry guys that's the only two calibers I am interested, in lots of people down on the Valk, plenty of other 6mm available. Not interested. Trying to find 6 ARC ammo and or brass next to impossible. 6.5 grendel not easy to find.

Any suggestions and or thoughts.?
Thank you!

Retired shooter

 

[Rocketvapor]

I bet bolt lug breakage is due to overpressure loading to 6 ARC bolt gun specs and firing in an AR.

 

[Hudge76]

I built a 6 ARC in the summer of 2021 as soon as I could get a barrel. I have reloaded for it and I also agree I bet the broken bolt lug is reloading for AR’s using bolt action data. I do know some people have had accuracy issues with certain barrels so be careful there.

 

[Retired shooter]

Leaning toward the 6ARC , still checking out a new complete BCG to eliminate the brokenness bolt lugs.
You find brass, or Ammunition anywhere. Figured the new upper as a winter project, might be spring before find ammo or brass.
Thank you

 

[Majday]

Saw 5-6 boxes at local sportsmans the Hornady match 108s

 

[The boogalorian]

Leaning toward the 6ARC , still checking out a new complete BCG to eliminate the brokenness bolt lugs.
You find brass, or Ammunition anywhere. Figured the new upper as a winter project, might be spring before find ammo or brass.
Thank you

I experienced a broken bolt. As others have commented above I believe it was from loading over max recommended charges. Not just a few rounds, but hundreds of rounds loaded over max. Bolt had almost (900) rounds on it when it broke.
The 6 arc has need a fun project that I have learned a lot from. Ammo is available on gun broker.
Good luck whatever road you chose.

 

[Rocketvapor]

New bolts materials help with the large rim calibers in an AR. Bolt thrust, a product of the hollow diameter of the case times pressure is greater for the big cases. Most other issues with parts and brass are AR tuning issues.
In order to shoot fast, pew, pew, pew, the AR needs lots of action and gas.
I shoot a 22 Nosler, both with Dogtown brass in a No-Gas AR and 22 NOSGAR brass in a gasser.
Slow fire and really don't have ripped rims, swipes, etc. that others complain about.

 

[Ray123]

Hello All
Another guy seriously considering a new upper for my AR in 6ARC. Had thought about 224 Valkrie. Doing lots of research, finding out about blown primer pockets. Looks to be some having bolt lug breakage in 6 ARC. Anyone care to share current information.

Equipment malfunctions, possible human error, both. Would like some imput before we go any further.
Sorry guys that's the only two calibers I am interested, in lots of people down on the Valk, plenty of other 6mm available. Not interested. Trying to find 6 ARC ammo and or brass next to impossible. 6.5 grendel not easy to find.

Any suggestions and or thoughts.?
Thank you!

Retired shooter

I have both 224 Valkyrie and 2 6mm ARC AR 15 rifles. I don't have blown primers or sheared off lugs problem ...never had a blown primer in the 224 and never sheared of a bolt lug yet. So take your pick just be reasonable with the reloading guidelines. I have a 6.5 twist in the Valkyrie and shoot 80 gr, 88 eldm & 95 gr SMK, If I shoot light bullets I go with the 223. The 6 mm ARC was first bought as a complete upper from Brownells the only way to get started when it first came out. But the Areo Upper with a Ballistics Advantage barrrel shot 2.5" groups at 100 yds. Put a 6mm ARC together with a Proof Research barrel and it shot the same match ammo into .5" on the first 5 shot group, on the same day as I shot a 2.5" group with the BA barrel....ordered another Proof barrel as soon as I got home to replace the BA barrel. ..Stainless steel no carbon wrap crap for me...so I have 2, 6mm ARC s.
The 224 Valkyrie was a little hard to dial in too but not as bad as the first ARC barrel, that never, which is on the shelf. It liked centering the bolt carrier as an accuracy step more than any cartridge I've tried, a huge improvement. I don't shoot light bullets in either cartridge, for the 6 ARC it's 108 eldm, 108 Berger, 110 Sierra MK, and 107 SMK, very few 105s and nothing lower. So bottom line, both work, but I prefer the 6mm ARC in the AR platform, probably because of the accuracy with the Proof barrels makes it easy to shoot good groups. If ya want bolt gun performance, Use a bolt gun...don't push the thin AR bolts to the breaking point, and don't expect 24" barrel velocities out of your 18" AR and blow primers trying to achieve thise velocities..and you won't have problems either. If I go with the bolt gun I choose nether, and move up to the 6mm Dasher. That's my experience and opinion it...and I don't buy complete uppers anymore..only 1 in 3 shot decent.

 

[Retired shooter]

Thank you to all,
Will check it out.

 

[Retired shooter]

Thanks Ray123
Will be staying with the AR platform, will be talking with barrel manufacturer today, hopefully get it ordered for a winter project.

 

[AzMandella]

Wouldn't using an adjustable gas block be a good way to avoid over preasuing the bolt . Just tune it till the action cycles consistantly .

 

[David Milisock]

Hello All
Another guy seriously considering a new upper for my AR in 6ARC. Had thought about 224 Valkrie. Doing lots of research, finding out about blown primer pockets. Looks to be some having bolt lug breakage in 6 ARC. Anyone care to share current information.

Equipment malfunctions, possible human error, both. Would like some imput before we go any further.
Sorry guys that's the only two calibers I am interested, in lots of people down on the Valk, plenty of other 6mm available. Not interested. Trying to find 6 ARC ammo and or brass next to impossible. 6.5 grendel not easy to find.

Any suggestions and or thoughts.?
Thank you!

Retired shooter

Ok this may get lengthy because you haven't specified a use for your rifle. If you don't mind long barrels the 224 and 6 ARC both work fine. The 6 ARC was a tad better at reaching out than the 224 but it's splitting hairs and I'm going from memory. Both cartridges are daisies in bolt setups.

I wanted a general purpose rifle, reasonable to carry in a vehicle with great in close (CQB) capabilities and be able to take medium game at reasonable ranges. That meant a shorter barrel, I went with a 16", the math on the 224 in a short barreled rifle is not very good. I went with a 6MM ARC with these parameters in mind, 52,000 PSI MAX and the slower powder that the case/rifle was designed for, LeverEvolution. I bought factory ammo to clock as a base to duplicate, I load ONLY to the formulas supplied by Hornady.
My supplies are readily available, my results are phenomenal, 1/2" 100 yards groups with an Aero Precision M4E upper and lower with a heavy barrel. A few extras, a National Match 2 stage trigger but the rest is basic. Felt recoil is less than my M1 Carbines, my AR15 A2 and my sons 16" Stag Arms SR1.

The 6MM ARC in an AR platform is no more than a 2 trick pony, STICK with 52,000 PSI, short barrels for general purpose rifles, again STICK with 52,000 PSI and longer heavy barrels for pretty great work out to 1,200 yards. I've seen exceptional work done on steel out to those ranges.

Even in a bolt rifle neither of these cartridges are rockets, but in they make the AR platform sing.

 

[rsbhunter]

Sold the upper I built in 6arc, alot of loading data was either at or over max....tired of trying to find cases,etc. Even some factory loads were one and done on primer pockets....made my decision when I started getting belted cases....rsbhunter

 

[gunsandgunsmithing]

Wouldn't using an adjustable gas block be a good way to avoid over preasuing the bolt . Just tune it till the action cycles consistantly .

No. Two different things. Bolt thrust is what breaks the bolts. Aside from timing, gas port regulation has nothing to do with the root cause, excessive bolt thrust...generally from too hot of loads. As mentioned, stay with 52,000psi or lower and bolt breakage shouldn't be a big issue.

 

[LVLAaron]

I called White Oak when the 6 ARC was announced and asked if they'd be making barrels. This is what they pointed me towards:

Hornady's New 6mm ARC

Hornady's New 6mm ARC

www.whiteoakarmament.com

 

[gunsandgunsmithing]

I called White Oak when the 6 ARC was announced and asked if they'd be making barrels. This is what they pointed me towards:

Hornady's New 6mm ARC

Hornady's New 6mm ARC

www.whiteoakarmament.com

Yessir. That article pretty much just says the obvious...keep it under 52,000psi and that target shooters are tipping the powder can too much. No doubt, it's a good cartridge but there have been 6ppc's a 6 grendels by other names for several years and this case is ultimately just a standardized version of either one of those. If anything, the straight 6 Grendel is the best of the three due to more case capacity. It makes a little more speed at the same pressures but it suffers the same fate if you tip the can too far. It's not a cartridge problem. It's not even a problem at all, but it is a limitation of the AR15 platform that is just being seen more due to the popularity of the case with it being standardized vs the ppc or 6 Grendel. Nothing more, nor less. Fine cartridges and a fine gun but a gun that has limitations below what we'd like to see.

Not to say I told you so but I predicted this very thing when it was first announced. Anyone with any experience with similar cases and knowing the ar bolt thrust limits could see it coming a mile away. Still a good case but it can't be loaded to 223/5.56 pressures. That's what people have a hard time digesting, is the additional bolt thrust generated by a "fatter" case ID.

 

[JimSC]

just put one together using mostly Aero parts, with a Criterion barrel chambered by Precision Firearms. So far just did a break in and then a rough 3 round load workup to get and idea of velocity using Accurate 2520 and Sierra TGK's with CCI 450's seated at magazine length. All of these loads are within Hornady recommendations and SAAMI specs for gas rifles, and it looks like there is some potential here for long range applications. The 4 flyers in the upper lefty were 2 sets of sighters @ 27.5. I use a adjustable gas block on all my Grendels and the ARC. I also remember to keep the pressures reasonable because of the decreased metal compared to .223 based cartridges around the bolt lugs

 

[Retired shooter]

Hello All
Thank you to all that have responded. My goal for the 6 arc build is ELR steel target shooting. So with that yes heavier bullets with longer barrel, using a bench, and bi pod.

Will be ordering when the manufacturer returns the call.

Now for the next question, for those of you that used the 6.5 grendel brass, ( and made our 6.5 grendel brethren mad) and resized and trimmed it , what brand of dies did you use.
I can now start collecting all the necessary reloading tools necessary. Oh well it's only money.!

Again Thank you all.

 

[LVLAaron]

Johnny's Reloading Bench on youtube has an entire in depth series on reloading for it. He's entertaining and a fellow KY boy. Give it a watch:

https://www.youtube.com/results?search_query=6+arc+johnnys+reloading+bench

 

[Rocketvapor]

Hope he did better than he did with the 22 Nosler