RE: 300 Ultra Mag
About 0.3" at 100 yards with Sierra 200 Matchkings so I shouldn't complain. But its a little finicky in seating depth. Which tell me it will finicky with temp changes also. So I blamed it on the throat. Haven't worked on hunting loads yet. Got some 180 Nosler Partitions loaded with Retumbo and 180gr Speer's ready to go for this weekend. But really don't plan on taking this thing hunting again. I think only lightweight these days. This is just my real real long range gun.
So you do your own reaming?