The .444 is in production right now, barrels have been broach rifled by Marlin in 1:20" twist, so far no one has one yet, I'm waiting for mine. I was told yesterday it would be another month or so before I get it. The current barrels have .4308" bores, SAAMI spec is.431 ± .001 and .4248" lands, SAAMI spec is .425 ± .001.
Tim