What are your thoughts on the new 6ARC

[usbp379]

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[TheRifleman]

So I am changing directions on my 6 ARC project. Instead of a 12.5 mini recce spare companion upper for my 5.56 11.5 SBR (stamp is marked 5.56 instead of multi), I'm going to convert a 16" mutt rifle into an actual recce with a 16' Compass Lake Criterion barrel in 6 ARC, in mid length, and provide the CMC bolt for headspace.

The plan is to use a BCM Mk2 extension with an A5H2 buffer using a green Sprinco spring. I am trying to keep the OAL down but cannot find any compensator or flash hider in either 6.5 or 6 with 5/8 threading that's small enough. I thought that the Vltor one would work but that threading on it is weird. Not sure if it's a typo or not but my Compass Lake is in 5/8. Any suggestions? I saw that Alexander had a 6.5 A2 but it's no longer being produced.

[usbp379]

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[BoilerUp]

So I am changing directions on my 6 ARC project. Instead of a 12.5 mini recce spare companion upper for my 5.56 11.5 SBR (stamp is marked 5.56 instead of multi), I'm going to convert a 16" mutt rifle into an actual recce with a 16' Compass Lake Criterion barrel in 6 ARC, in mid length, and provide the CMC bolt for headspace.

The plan is to use a BCM Mk2 extension with an A5H2 buffer using a green Sprinco spring. I am trying to keep the OAL down but cannot find any compensator or flash hider in either 6.5 or 6 with 5/8 threading that's small enough. I thought that the Vltor one would work but that threading on it is weird. Not sure if it's a typo or not but my Compass Lake is in 5/8. Any suggestions? I saw that Alexander had a 6.5 A2 but it's no longer being produced.

You don't have a suppressor choice driving which MD you need?

[alamo5000]

So I am changing directions on my 6 ARC project. Instead of a 12.5 mini recce spare companion upper for my 5.56 11.5 SBR (stamp is marked 5.56 instead of multi), I'm going to convert a 16" mutt rifle into an actual recce with a 16' Compass Lake Criterion barrel in 6 ARC, in mid length, and provide the CMC bolt for headspace.

The plan is to use a BCM Mk2 extension with an A5H2 buffer using a green Sprinco spring. I am trying to keep the OAL down but cannot find any compensator or flash hider in either 6.5 or 6 with 5/8 threading that's small enough. I thought that the Vltor one would work but that threading on it is weird. Not sure if it's a typo or not but my Compass Lake is in 5/8. Any suggestions? I saw that Alexander had a 6.5 A2 but it's no longer being produced.

Are you going to run it suppressed? Barrel length is up to you--but I will give my .02. It all depends on how far (realistically) you plan to shoot and how you have it set up. Have you given thought to a pinned 14.5? It would allow a complete rifle (recommended) without another stamp.

As far as gas systems go this is my experience. I have a 24" barrel with a rifle length gas. Even though I have an adjustable gas block I had a time with mine being over gassed. I ended up using an H2 or H3 and an XP spring to slow everything down enough. I had seen before that many manufacturers were doing rifle +1 or rifle +2 lengths, and after using a regular rifle length I can understand why. While I don't know exactly, my hypothesis is the amount of powder and resulting gas is more--a whole lot more--than I was originally expecting.

Long story short, I don't know if it's a universal thing, but I would plan on erring on the side of getting much heavier buffers, especially if you plan on running a can.

As far as muzzle threads go, they will be 5/8. Most places do not make anything 6mm. Been down that rabbit hole before. 6.5 works great and I would think even a 30 cal would be ok. I have Griffin mounts on everything as that's what my cans are. My 6 ARC one is a 6.5mm version. They do make several. That said, if you just want a plane jane A2 style, go with a 30cal. I am not sure how it will impact 'flash hiding capabilities' but it will definitely work on your barrel should you go that route.

[TheRifleman]

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Already watched it, I won't be pushing it that far anyway and for that shorter barrel is by being 3.5 inches less it'll be perfect for my needs.

[TheRifleman]

You don't have a suppressor choice driving which MD you need?

Yeah but that Sandman K is already on another rifle and I don't share cans or anything else other than a quick detach bipod between them all. I think that I may have gotten it down to just buying one more and either use the FCD 6310 or the Cobalt RCB-KM Warden copy that also uses Keymo.

[TheRifleman]

Are you going to run it suppressed? Barrel length is up to you--but I will give my .02. It all depends on how far (realistically) you plan to shoot and how you have it set up. Have you given thought to a pinned 14.5? It would allow a complete rifle (recommended) without another stamp.

As far as gas systems go this is my experience. I have a 24" barrel with a rifle length gas. Even though I have an adjustable gas block I had a time with mine being over gassed. I ended up using an H2 or H3 and an XP spring to slow everything down enough. I had seen before that many manufacturers were doing rifle +1 or rifle +2 lengths, and after using a regular rifle length I can understand why. While I don't know exactly, my hypothesis is the amount of powder and resulting gas is more--a whole lot more--than I was originally expecting.

Long story short, I don't know if it's a universal thing, but I would plan on erring on the side of getting much heavier buffers, especially if you plan on running a can.

As far as muzzle threads go, they will be 5/8. Most places do not make anything 6mm. Been down that rabbit hole before. 6.5 works great and I would think even a 30 cal would be ok. I have Griffin mounts on everything as that's what my cans are. My 6 ARC one is a 6.5mm version. They do make several. That said, if you just want a plane jane A2 style, go with a 30cal. I am not sure how it will impact 'flash hiding capabilities' but it will definitely work on your barrel should you go that route.

I have and I may just do that, because Compass Lake does give this option with the lengths. Three in fact using a Criterion blank.

Good advice with getting additional and heavier buffers. And I like having spares of everything. The 5.56 barrel that's coming off the rifle to converted? A Sionics and it's a great barrel, perfect for later if needed for my recce rifle in 5.56.

[Former11B]

Food for thought from Rainier’s F1 FAQ

Your Form 1 was approved for a specific caliber, overall length, and barrel length. However you are allowed to “temporarily” change the upper length or caliber but only if you maintain the original upper and ability switch back afterward. If you sell the upper and switch permanently to a different upper then you would need to send a notification to the ATF letting them know of the official change. You don’t pay the stamp or go through the Form 1 process again, just a notification.



https://www.rainierarms.com/faq/sbr/

[TheRifleman]

Nice!! Thanks! Looks like 12.5 is back on the table again, boys.

[alamo5000]

Nice!! Thanks! Looks like 12.5 is back on the table again, boys.

I have had the thought of a 12.5 in the back of my mind as well, but at present I have many other projects and rifles that I don't shoot enough as is.

[TheRifleman]

I have had the thought of a 12.5 in the back of my mind as well, but at present I have many other projects and rifles that I don't shoot enough as is.

I have the Faxon 12.5 and the GLx 1-6 PA Griffin both on order, which were the last two pieces of this puzzle. However I am going to leave them as parts and not assemble until this recent buying scare is over. I want ammo in bulk enough to stash and also to shoot and weather it out between the scares, not occasional ammo at inflated prices. Worse case I wait. Not a bad first world problem to have though despite it all.

[usbp379]

Tinny sound but some interesting info.



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[usbp379]

Talking competition but still probably applicable to hunting or general rifle applications.



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[FortTom]

I think your second sentence really sums it up. All these 1000 yard cartridges... but who shoots at 1000 yards consistently or even has access to a range like that? That's a small subset of a small group. I think that's what really holds up these long range platforms.

Sort of my thoughts too. I see a military application for it, but not much in it for me to build a rifle around it. I'm not a 650 to 1000 yard shooter, either..FT