What can you tell me about the above rifle?
Not much more that that Tweet. PSA just teased their new Sabre Mk12 Mod H (looks like).
I can tell you their "Sabre" line is their shot at a more duty grade AR. Nicer tolerances and finishes, better parts, usually around a grand for a build on forged recivers (which that picture looks like). They get good reviews against like BCM or FN factory guns.
On the Mk12 front, very briefly the Mk12 Special Purpose Reciever (later Rifle) was a USSOCOM program starting early in the GWOT to let M4's have a little more reach. The Mod 0 and Mod 1 versions had a specially profiled 18" barrel mated to a flat top M16A4 upper and usually about a 10x variable scope (usually Leupold or NightForce). Once it became a whole rifle and not just an upper they got KAC two stage triggers. The later Mod H variant had a 16" barrel (which is what PSA's looks like). All variants came with an OPS inc supressor, bipod, and one of the versions of the PRI Carbon Fiber Freefloat handguard. THe handguard is what makes a Mk12 so recognizable.
Combined with MK262 77gr ammo a Mk12 can get solid, effective hits on a torso out to 800ish yards, which really helped out units that were mostly carrying M4s in Afghanistan. Marcus Lutrell pretty famously had a Mk12 during Operation Red Wings.
I pretty regularly take my Mk12 mod 0 (ish) to 1000yds, but it's trans sonic by then and I'm not sure how effective it would be. At 800 it still hits the steel pretty hard.
