How Effective is the MK12?

[okie]

It's a best case scenario for 223, so you're not going to do much better without stepping up to 6mm. It's almost a bull barrel, and the silencer they chose is unclipped for maximum precision and minimum POI shift. It also has two alignment points to ensure bore concentricity. I'm not sure what thread class the government Mk12 barrels had, but I would be surprised if they weren't a bit tighter since they were a custom job. All in all, I speculate that an alignment rod would probably be dead center.

There are two areas where they should have done better, where a civilian making his own version could do better. The Mod 0 had the benefit of the somewhat monolithic handguard. I'm not sure why they went away from that. Maybe it proved to be ineffective. But you could definitely help yourself using a real monolithic upper of some kind. Normally not worth the weight, but since it's a monster already a few more ounces won't make any difference.

The other area where you could improve is the barrel length. The Army wanted 20, the Navy wanted 16, so they compromised at 18, which was a mistake. Kind of the worst of both worlds and the best of neither. The Mk12 program was started to standardize SPRs across SOCOM, and basically combine the Navy's RECCE program with the Army's NM style M16s they were using. A civilian making his own version would be better served by either a 20 inch rifle or a mid length 16 inch. Or even a carbine length SBR for that matter. Reducing length will sacrifice a little range, but should actually increase precision within its effective range. Mk262 isn't exactly flat shooting from any barrel length, so I doubt you would see a major loss of ballistic performance either way, within reason.

There have also been improvements in optics since the Mk12. An S&B 1-8 short dot scope would be absolutely stunning on that platform. I've also heard virtues of using an ACOG on them, and that might be a very attractive option if you did an SBR variant.

As for the silencer, I don't believe OPS is still around, but the Surefire silencers are pretty much modernized versions of them. You could probably just go with any of the full sized Surefire cans and be just as well off.