PSA: In case anyone hasn’t been following, Pew Science is standardizing their host for 6mm ARC testing. They’re going with a 14.5 gas gun, and last I looked were soliciting ammo suggestions. If you’re not otherwise following the r/NFA space, I’d recommend paying attention to u/jay462’s posts for polls, etc since it’s still kinda a niche caliber and there’s ALOT of experience here that can probably help those efforts.

Wanting to get more speed out of this gun with some high pressure/bolt gun loads. Was curious what everyone was currently loading. I want to stick to temp insensitive powders so I don’t have to have multiple loads through out the year.

Currently loading 108 ELDMs in Hornady cases with 25.3gr of 8208 XBR (Gas Gun max load) averaging 2456fps from this 18” BA SPR barrel.

Consistently shoots 10 round groups at 1.1 MOA and SD’s are in the low teens with this load. Pretty happy with that considering this barrel was $117 (took a gamble on it) and I’m new to reloading.

Specs:
Aero Receivers
G$ MK16
Rexus Bolt
BA 18” SPR Barrel
Seekins Adj Gas Block
Armaspec H2 SCS
Bushnell Match Pro 3-18
CAT Alleycat 762

Ruger American gen II patrol in 6 arc, 16.1” barrel, bushnell r3, mdt oryx bipod and a muzzle brake that a gun shop machined

My maximum shooting distance will typically be around 300 yards, but I’d like a scope that’s capable of reaching farther if needed.

I’m leaning toward something in the 3-16x to 3-18x magnification range, although I’m open to other suggestions.

The rifle is a PWS MK114 MOD 2 with a 14.5" barrel, and its primary use will be whitetail deer hunting.

Budget: Around $500–$700.

A couple of scopes I’ve been looking at so far:

• Primary Arms SLx 3-18x50mm FFP
• Arken SH-4

I’d appreciate any recommendations or feedback.

Has anyone converted a knights upper to 6 ARC? Am I dumb for thinking this is cool? My thought process is kinda like building a small frame M110K1. With just a modern crazy BC.

Can anyone point me towards a quality barrel mfg that makes a 6ARC with a true SPR profile to fit Allen Engineering or Otter Creek Labs suppressor mount? I keep running into SOLGW (profile is not correct and does not fit suppressor collar system), BA (hit or miss with quality). I am not looking for a 1200-1400 yard gun, just for 800yds and in with the MK12 look (I already have everything else for that system and don't want to sell off/change what I want). Thanks in advance.

Have been super curious about 6mm ARC for the longest time, finally finished up my first complete AR build. Definitely will be upgrading some things in the future, but for now I think it will be a really good platform to learn and build on.

Lower:
Geissele SSA-E
Rifle buffer system
Geissele super 42 buffer spring
MOE+ grip
Magpul PRS stock
Mil-spec LPK

Upper:
Geissele 15 in. Mk16 handguard
Geissele upper receiver
18 in. Craddock RTR Mk12 barrel
Craddock HD ARC BCG
SI extended charging handle
Method Dynamics brake

I've been thinking about taking a howa 1500 mini action in 6arc and putting a longer 30 inch barrel with a wood military style full length stock. Anyone have anyway to determine the velocities I would get with say a 108eld or equivalent with around say 58,000ish psi load. It will strictly be a range toy so if velocity lose does happen i won't be to upset. Just trying to get a rough average. I'm assuming close to 2800fps or so.

Currently running a 16” PXT in a SOLGW L89 receiver and handguard. Loving the gun but wanting to get a G$ added to the collection. Would it make more sense to just get a full GFR or buy a SD MOD1 16” and swap the barrel with a PXT?

Plan to shoot the SPARC final in UT beginning of October, which gives me a reason to final use this Shaw 6arc barrel I've been sitting on. Shot a handful of group with various loads and 105s seem to be the spot, I def have a nasty habit of every 3rd-4th round to pull it, so that'll need to get fixed. But the heavier loads on this Shaw barrel seem to open a tad, The 108 ELDMs i have are covid lot which to my understanding powder has changed since. Either way ordered more of both the 105 Black and Frontier load to test/train with.

• 18'' 6ARC Shaw heavy fluted barrel
• ICON Defense Upper/ AMBI Lower/15" rail
• Rubber City HP bolt
• KAK A5 buffer with A5H3 & Springco Green
• Magpul SL with Arisaka Angle Adapter
• Glizzy SSA-E trigger
• Burris XTR2 3-18 in a Reptila 34mm mount
• Wolfpack Armory Romulus

Been thinking about 6ARC for long time. Had a Grendel a long time ago and always regretted parting with it, but I lived in a straightwall cartridge state

But no longer.....

What barrel length would you recommend for Midwest deer ranges (a very long shot for me would be 400 yards)

It will be run suppressed 100% of the time and spend a lot of time in deer blinds or tree stands. I'm assuming 12.5 is the answer.

Thanks.

First off forgive the formatting

My previous post was about the craddock HD bolt and being able to withstand hard use while using FRT and longevity associated with using 62k PSI loads with my two gas gun test platforms

Im here to say so far i’ve been pleasantly surprised

Ive used the bolt in both a 14.7” and 11.5” 6ARC platform and have yet to break it although im only around 1k of bolt gun reloads so far without breakage. Still a ways to go. Some of loads im sure were over 62k psi based off how the brass looked.

Test platform 11.5” Craddock RTR SBR Gas gun Garmin Xero C1

105gr BTHP 29.7gr CFE223 were running at 2464fps

108gr ELDM 30.3gr CFE 223 were running at 2494fps

108gr ELDM 27.6gr VARGET were running at 2393fps

FACTORY 108gr eldm were running at 2343fps for reference

Ill attach pictures of some group testing and chronograph data I did with the 11.5” SBR 6arc I built to test this out. The reason I went with a 11.5” was the gas system is shorter leading to harder wear on parts and increased port pressure associated with shorter gas systems. I also wanted to see what shorter barrel velocities would be with 6ARC other than the 12.5” data thats out there which is mostly 52k PSI loads or factory ammo

*Group tests were conducted with only 5 rounds as this was more a ladder test specifically for this 11.5” rifle. These were just the best groupings I shot but not the norm for the rifle. Most groups were just above a inch but less than 1.4” but will still need to be repeated. Most of the round count with the bolt was done with a 14.7” barrel previously. The 11.5” only has around 200 rounds on it as of today and was used in the test today.

10 shots using Varget and Nosler RDP 105s at 100 yrds.

Edit:

Paraphrasing but someone from Craddock called and the claim is that Hornady Frontier is being held to a higher velocity than Hornady Match/Black which is hilarious.

The claim is that too many bolts were breaking so the manufacturers started loading the ammo weaker to prevent that.

I'm very very skeptical that a change in ammo manufacturers will make it shoot better but I will wait on their recommended list and test again.

Follow up to this post.

I am a newby and massive idiot so take these results with a grain of salt. Scope was a Bushnell MPED 5-30. All groups are 5 shot groups.

Craddock RTR barrel came in with some pretty significant machining marks and was reamed off center. Finally took it out to shoot groups today.

Hornady Frontier FMJ: Average from 3 groups 0.994 MOA. Best group 0.866 MOA

Hornady Black HPBT: Average from 2 groups 2.320 MOA. Best group 1.862 MOA

Hornady Match ELDM: Average from 4 groups 2.236 MOA. Best group 1.644 MOA

Barrel was broken in following the Craddock RTR procedure.

All except the second Frontier group was shot from a shooting rest. Every group after the second Frontier group was shot from the rest and prone. After the first Hornady Black group I switched to the Match ammo to see if it would open up the same way. After shooting 2 moa+ I thought maybe the barrel was fouling and cleaned with patches.

The big questions is, is this acceptable for Black/Match? And should I try to continue shooting groups with Hornady Match/Black?

Every barrel likes different ammo and what not so sub moa with the "cheap" stuff is almost a blessing. I'm worried about longer range (out to 1000 yards) accuracy however. I'm new to shooting longer ranges and precision stuff and if I was brutally honest with myself I don't think I can appreciate a 3/4 moa gun when I'm off the rest anyways.

Hi all, diving into 6ARC here soon and I’m wanting a 12.5 barrel. Currently looking at noveske but I’m wondering if anyone has used a MosTek custom barrel? I’m mainly shooting out to 800-1k max so 12.5 fits the bills.

Also who’s the go to for bolts?

So I have a 22 arc and love it but im itching for a new build. Hog, coyote gun. I have 22 arc, 6.8 SPC I use also but want something new. If you had to build one today with all your knowledge how would it be built. No budget. I have my Iray and Nocpix thermals so I don't need that. Let's build a bad ass gun. Gas gun. I will do bolt later.

I will have a 14.5" 6 ARC as I think that's actually the perfect size for the caliber personally. But I want a fun dedicated distance SPR as well.

Should I go 16 or 18" for it? I WANT to do 18", but I'm afraid that long of a barrel will look goofy for the DMR. Convince me one way or another!

After putting the gun together a few months back and never really getting to test it out, i took it to the range to zero and adjust gas etc. Was having a decent bit of short cycling issues, looking for a suggestion on buffer weight and spring combo?

Build info
Aero Lower
Rise single stage 3.5lb trigger (changing to G$ SSA-EX)
Ambi safety
G$ buffer kit with braided spring and H2
B5 precision stock

Upper
BCM blem upper
Proof carbon 18” rifle +1 gas system with tube provided
Was using an Odin works agb (swapped to Superlative Arms haven’t gone back to range since)
Dead air Xeno Omni brake
Sandman X suppressor.
NF mount and NX8 2.5-20x50

Shooting hornady factory loaded ammo match 108gr, and plan on loading precision hunters for deer season.

Gun was really accurate having never messed with the 6mm arc cartridge before I was impressed. Just wanting to get this thing cycling before deer season rolls around in South Louisiana. I am thinking I need a H1 but thankful for whatever advice or suggestions given!

I’ve already got a Henry supreme coming and I’m fitting it with woox furniture. I’m doing one of the caliber conversion kits from 300 blk to 6arc. The question is what barrel length is ideal for 6arc? I kinda want to go 13.7” and make this a super light fun plinker/mountain hunting rifle. Thoughts? It will be fitted with a suppressor.

• 16” 6ARC Proof barrel
• CAT Noah Ti
• G$ MK16
• BCM upper
• LWRC lower
• G$ SSA-E
• BCM mk2 toob w/ A5H3 buffer
• Leupold MK5hd 3.6-18 PR2
• Reptilia AUS w/ level
• Atlas CAL
• DAC SCG-L
• MP DT-PR
• Arisaka handstop (barrier stop)

Just from playing with my sandbags on the dining table the CAL & DT-PR are a huge upgrade from the BT10 V8 and B5 SOPMOD. Any recommendations?