Custom 6 ARC Conversion

coldboremiracle

Freelance Sharpshooter
Full Member
Minuteman
  • Jul 7, 2009
    5,346
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    Utah, north
    www.coldboremiracle.com
    I did this once before, and I liked it so much I decided to make another. I love this little rifle!

    Custom 6 ARC WLVRN

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    I think you would get a higher quality magazine, slightly lower weight, higher velocity, easier handload, similar recoil, and off the shelf operating system (.473 bolt).
    There are higher quality magazines for the GT than for ARC/Grendel? Lower weight of what? Gt's are easier to load than ARC's? Neither of them are "off the shelf".
     
    There are higher quality magazines for the GT than for ARC/Grendel? Lower weight of what? Gt's are easier to load than ARC's? Neither of them are "off the shelf".
    Why put 6ARC in a large frame platform when you can put a cartrididge designed for a large frame platform in the large frame platform? GT is easier to load than ARC and there is factory ammo.
     
    Why put 6ARC in a large frame platform when you can put a cartrididge designed for a large frame platform in the large frame platform? GT is easier to load than ARC and there is factory ammo.
    It isn't a large frame, it's both. How is GT easier to load than ARC? loading both is easy, and the ARC has a lower powder charge. There is WAY more ARC ammo than GT, not that I care because they are both easy to load.
    What did you mean there are higher quality magazines? Is there some magazine out there I don't know about? And you still didn't explain what you meant about lower weight with the GT? And if it was lower weight, with higher velocity, then the recoil would be higher not lower.
     
    It isn't a large frame, it's both. How is GT easier to load than ARC? loading both is easy, and the ARC has a lower powder charge. There is WAY more ARC ammo than GT, not that I care because they are both easy to load.
    What did you mean there are higher quality magazines? Is there some magazine out there I don't know about? And you still didn't explain what you meant about lower weight with the GT? And if it was lower weight, with higher velocity, then the recoil would be higher not lower.

    Large frame with adapters, no? Take the adapters out and run it with 308 mags. I've never used Geisele mags but Grendel mags in general leave a lot to be desired. There are plenty of higher quality 308 mags. ARC has capacity constraints, GT doesn't. Your platform doesn't have the 52kPSI ceiling an AR does. Port pressure of GT is pretty close to 308, use all of the 308 parts minus the barrel. Why get hamstrung by the adapters and case capacity of ARC when there's native solutions? As I understand it, the accuracy issues don't appear with lower weight projectiles, maybe you can speak to that?
     
    Large frame with adapters, no? Take the adapters out and run it with 308 mags. I've never used Geisele mags but Grendel mags in general leave a lot to be desired. There are plenty of higher quality 308 mags. ARC has capacity constraints, GT doesn't. Your platform doesn't have the 52kPSI ceiling an AR does. Port pressure of GT is pretty close to 308, use all of the 308 parts minus the barrel. Why get hamstrung by the adapters and case capacity of ARC when there's native solutions? As I understand it, the accuracy issues don't appear with lower weight projectiles, maybe you can speak to that?
    I guess if you look at it as a large frame with adaptors perhaps, I don't because it was designed to operate this way, not adapted from one to accept another. I don't really plan on shooting large frame calibers from this one, as I have another one that has quite a selection of bigger cartridges like 308, 6.5, 450BM and such.
    I was unaware Grendel mags left anything to be desired, they have always worked just fine for me. And I am not really concerned about capacity with ARC or GT, for the most part I shoot low volume strings of maybe 3-4 rounds. The only reason I wan't an ARC in this platform is to have the ability to shoot 100gr class bullets for varmints and smaller big game. I mostly shoot .223 through this rifle for affordability and efficiency, the ARC is a slight step up in cost and bullet weight. The GT would be a bigger step up, but I already have that option. Plus I don't want my expensive GT brass getting beat up and damaged by autoloading.
    I haven't noticed any kind of accuracy issues with the ARC be it 58gr up to 105 grain. I haven't tried anything bigger like the 109's or 112's that I shoot in the GT, mainly because I get the Hornady 105's for dirt cheap and they shoot fantastic out of all my ARC's and the GT too.


    Curious how you know what the pressure ceiling is on my gun? I thought AR's were higher than 52k, like 58k, and since the WLVRN shoots higher pressure cartridges over 60kPSI I don't understand where that point is coming from or how its relevant.
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    Curious how you know what the pressure ceiling is on my gun? I thought AR's were higher than 52k, like 58k, and since the WLVRN shoots higher pressure cartridges over 60kPSI I don't understand where that point is coming from or how its relevant.
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    All Grendel based cartridges have a pressure ceiling of 52kPSI due to the AR15 Grendel bolt. ARC is, theoretically, loaded within that pressure window. The WLVRN doesn't use an AR15 bolt, it was designed as a large frame. The small cartridge conversions use the same trunnion and bolt diameter as the the large cartridge trunnion and bolt. The operating chamber pressure ceiling of the WLVRN is 62kPSI, which is what CM is.

    I was talking about case capacity, not magazine capacity. ARC is constrained by case capacity. Nearly all of the higher velocity loadings are ball powder as a result.
     
    I prefer 95gr SMK as a sweet spot for these Grendel based 6mm's because the recoil or rifle upset is noticeably less than 105, and the BC is close to 105. Because you get a little more speed, which is almost 100 fps more/@2870 fps/ in my 22" barreled Fat Rat, the wind drift is the same as 105gr. It makes for a really soft shooting AR and isn't too far behind my 6mmBR bolt rifle using 107gr in performance.

    It might partly be the heavier BCG in the large frame 243 I used to own but rifle upset was much more than that of my Fat Rat.
     
    I was talking about case capacity, not magazine capacity. ARC is constrained by case capacity.
    I suppose, but I knew that going in, and is part of why I chose it.
    The only reason I wan't an ARC in this platform is to have the ability to shoot 100gr class bullets for varmints and smaller big game. I mostly shoot .223 through this rifle for affordability and efficiency, the ARC is a slight step up in cost and bullet weight. The GT would be a bigger step up, but I already have that option. Plus I don't want my expensive GT brass getting beat up and damaged by autoloading.
    Plus all the same arguments could be made in favor of 6CM or .243 over the GT, and I don't really want those either.

    I prefer 95gr SMK as a sweet spot for these Grendel based 6mm's because the recoil or rifle upset is noticeably less than 105
    I suppose, but this thing doesn't hardly kick with the 105's so thats not really a concern to me. Plus I have a good supply of the 105's and they shoot great from ALL my 6mm's.
     
    That looks amazing! I really dig the 6 ARC as well, have 3 at this point and took two deer with the 12.5" this year, but a 16-18" bullpup with the same or less overall length as my SBR would be awesome for deer thumping. I have a GT as well, and like it but understand your choice here. Is the ARC an option for desert techs without going custom?