6mm ARC - Rifle Conversion

[birdshooter]

I am not one to become enamored with new cartridges and generally try not to add anything new to my accumulation that I need to stock. However, the 6mm ARC caught my eye but not for use in the AR platform.

I have a Mossberg MVP Patrol in 5.56. It is handy and my 11 year old has used it to hunt deer with tough bullets (Barnes). I certainly know that the 5.56 is not the best option for deer. My question for you rifle loonies out there, do you think it would be possible for this gun to be converted to 6mm ARC? I know a new barrel and magazine are required. Not an issue. My concern is the bolt. As I understand, the bolt face would have to be opened up to accept the larger case head of the 6mm ARC. The likely problem is the design of the MVP bolt. It has a hinged lip at the bottom that is necessary to strip a cartridge out of the magazine. What do you guys think, is there enough room on the MVP bolt face to be opened up and still have proper function?

 

[dusty3030]

My question would be why?
The Mossy is a fine little rifle, but the cost of doing the conversion you could have bought another one in .243 Winchester, which would be a little better than the 6mm ARC with no appreciable gain in recoil.
Savage, Mossberg and Ruger all make fine compact bolt guns in .243 that are very affordable. Use the rifle you already have for targets and coyotes. Both have their place.

 

[dusty3030]

OK - I spoke too soon. I didn't realize the mossy was so much like a Savage 110 design with a floating bolt head.

The MVP comes in .224 Valkyrie which is based off a .30 Remington case (6.8 SPC bolt head sized). This would have a .422 case head.

The 6mm ARC is based off a Russian x39 case which has a .438 case head.

The MVP is also a barrel nut design.

If I were you I'd try and buy a .224 Valkyrie bolt head and have it fitted to the new 6mm ARC barrel. There would be much less to remove on the bolt face and it would put your ejector plunger in a better place as well as probably eliminate have to change up the extractor much if at all.

Get a new barrel nut from Pacific tool and you'll have a switch barrel rifle.

Mossberg MVP Barrel Nut - Pacific Tool and Gauge

 

[WR Moore]

OK, let's be practical.

The ink is still wet on the first 6 mm ARC article. The likely prospect of factory ammo in the caliber (with/without hunting bullets) or brass & dies (plus other components and loading data) for reloading same in the near future is pretty much zilch, zip, zero, nada. Don't be too quick to jump on a bandwagon.

If dusty3030 is correct and the bolt heads are easily changed, 6.8 SPC would seem a likely prospect, again if ammo/components are locally available.

If you reload and you have components and want to try something else, rebarreling to something like 7 mm TCU might be another way to go. Don't have to mess with the bolt/bolt head that way. IIRC, Wilson Combat had a .25 caliber cartridge based on the .223 case that might be of interest.

However, you need to watch sectional density of likely bullets to maintain decent penetration. Heavy for caliber bullets in .223 may do better than you expect. I'm not that big a fan of 6 mm for deer.

 

[vonn]

Interesting thread as I also like what I have read on the 6mm ARC but more for the AR style rifle. I also am not overly impressed with the performance of 243 on deer if poor shot placement rears its ugly head.

 

[birdshooter]

Great thoughts all. I really appreciate the input. It is certainly not practical cost wise but at this point I am fortunate enough to have plenty of off the shelf guns and am trying to get into a mentality of doing something different rather than just purchasing a new arm.

I am definitely not one to jump on every new cartridge and the ARC needs to make a lot of headway. I do reload and that helps.

If I move on this I will keep you posted.

 

[MrOverlay]

6 ARC

I just received my 6 ARC rifle back from Advanced Weapons Technology and am very pleased with it. First handloads group measured .468 (5 shots) 100 yards with the Hornady 108 ELD. The magazine required a custom spacer but feeding is flawless. Am I trying to re-invent the wheel, well maybe. Wouldn't be the first time though. Also factory Hornady 108 ELD shot very well also. My gun seems partial to the 108 ELD bullets. I've hit 4 inch plates at 400 yards with ease.

Gary