12-12-2014, 02:41 PM
The compound throat helps accept a wider variety of different shape bullets in an effort to center the bullet into the barrel. The 264 LBC chamber was designed to shoot the 123 grain Sierra Match King best. AR Stoner/Liberty sold a large number of out of spec 6.5 Grendel chambered barrels. They could not re cut the compound throat into their previously short chambered barrels. Liberty basically changed to the Grendel II chamber as a fix for their short out of spec compound throat 6.5 Grendel barrels. Liberty basically lengthened the free bore so their 6.5 barrels can supposedly shoot long heavy bullets accurately (like 140 grain or heavier). Basically this a marketing strategy to cover their previous mistake. I really think the Grendel II chamber is cheaper and easier to machine with less chance of barrels not functioning. Since the 6.5 Grendel is industry standard it has to conform to Alexander Arms chamber design to be marked 6.5 Grendel.