I use that bullet in my .243, which is why I suggested doing comparisons of dimensions and capacities. My Sako is a 19" carbine, so I guess I'm getting no more than around 3,000 ft/sec. With a long barrel, probably around 3,400 or so.
Hart barrels have excellent reputations. The main thing to check on any used rifle is the leade. If it's not burned from extensive use, it's a "buy".
You're from BATFE? Come right in! I use all your fine products!