I am planning a build a mk12 mod 0 clone but in 6 mm ARC. I Already have a proof barrel, however it’s rifle length +1. So my question is, do you think it’d be possible to use this barrel for a mod 0 clone? I know everythinf is pretty tight on the mod 0 so it may not work. However Id hate to not use this barrel since it was free. Below is the barrel I have which I have as well as mk12 specs
Mk12 mod 0 in 6mm ARC
- Thread starter G3A3A1
- Start date
Problems: The standard PRI MK 12 Mod 0 forend will be too short for the +1" gas system. The PRI flip up front sight won't work with the short Proof gas block journal. There's no shoulder on the Proof barrel for the Ops-Inc barrel collar. I don't know if you can get an Ops-Inc style muzzle device threaded 5/8-24 for the Proof barrel or not.
The idea of a modern 18" 6mmARC SPR is however very sound.
The idea of a modern 18" 6mmARC SPR is however very sound.
What about seeing if Ron will do a custom extension similar to the M4 Extension Adapter?
Allen Industries
Allen Industries
I think you are trying too hard to put a round peg into a square hole. You did not mention running suppressed, but that is an entirely different set of issues.
I like the idea of a 6 ARC on a Mk 12, for sure. As a builder of Mk12 riles, I would personally see that as a possibility, but given the other projects on our plate, maybe a 2024 offering. But the barrel needs to be profiled correctly. As @MSTN mentions, you have gas journal issues, gas tube length, lack of a shoulder for the collar. Perhaps gas port size if running suppressed....
If I were you, I would put that barrel to good use and get a good receiver set host and MLOK rails. The potential of 6 ARC is there, but not everything can be 6 ARC overnight. There are some other practical issues that are causing some builders to look at dedicated 6 ACR receivers and BCGs. I am no expert on 6 ARC, just learning, but it is not as simple as a move from .308 to 6.5 CM.
I like the idea of a 6 ARC on a Mk 12, for sure. As a builder of Mk12 riles, I would personally see that as a possibility, but given the other projects on our plate, maybe a 2024 offering. But the barrel needs to be profiled correctly. As @MSTN mentions, you have gas journal issues, gas tube length, lack of a shoulder for the collar. Perhaps gas port size if running suppressed....
If I were you, I would put that barrel to good use and get a good receiver set host and MLOK rails. The potential of 6 ARC is there, but not everything can be 6 ARC overnight. There are some other practical issues that are causing some builders to look at dedicated 6 ACR receivers and BCGs. I am no expert on 6 ARC, just learning, but it is not as simple as a move from .308 to 6.5 CM.
Maybe sell the barrel and get one that meets the specs you are looking to build?
Become a supporter and sell it in the marketplace.
Path of least resistance.
Become a supporter and sell it in the marketplace.
Path of least resistance.
This is what I will do. my friend gave me the barrel so I wanted to use it butni may have to buy one with a rifle length. Although I’m a little worried about 6mm arc reliability. As others has said it doesn’t seem as simple as 308/6.5 or 556/300
Not exactly the SPR handguard setup but I have a mk12 ish rifle, but I ran a 15” PRI on my 6mm ARC. Rainier Arms barrel 18” with a Rifle+1.
Not the traditional one with the cool front sight, but scratches the itch for me.
Not the traditional one with the cool front sight, but scratches the itch for me.
. You deserve to be told if you haven’t
MK 12 Mod H in 6 ARC - 16" Proof. .5MOA groups with factory 108 ELDM and will ring steel all day at 1,000 YD... transonic around 1,050 YD. Yes the gas block sticks out of the hand-guard and you can't run the nostalgic OPS INC clone cans, but the increased performance more than makes up for it.
