If that is the actual picture on the PSA website, that CHF barrel has been around for a few years. It looks exactly like the Alexander Arms "16" Tactical" barrel that was dropped from the line in 2014. Page 9 from the 2013 Alexander Arms catalog lists it as "The Grendel Tactical rifles are available in 7.5 twist rifling in mil spec chrome lined barrels. The M4 type is cold hammer forged, proof tested and mag particle inspected." If you zoom in on the PSA photo you can make out the rollmark on the top front of the barrel (where it is on the AA version, too.) It says "MP then the fancy F over the N in the oval 6.5 GRENDEL 1/7.5". I would guess that it is threaded 9/16-24 at the muzzle and uses a .136 bolt. I think the 1-7 twist is a typo. Obviously there was a 6.5 mandrel made for hammer forging when AA had the barrels made and it is back in service at FN. The 203 cut is silly, but it didn't prevent me from getting three of them when AA was selling them.