RE: 338 ultra mag
You will probably have to look on the used market. I've seen Browning, Remington, & Winchester rifles chambered for this round. My cousin owned one in a Remington BDL. Honestly, the round wasn't bad if firing free handed. The round was just awful from the bench. I mean it would rattle your teeth. I hunted with the rifle once and shot a 210 lbs. sow that was lying down with her rear towards me. A shot just below the tail flipped her end over end. I was using Remington factory 250 gr. bullets at the time. This caliber is definitely enough for any animal on the North American continent. My cousin also worked up an extremely accurate load with the 250 gr. Partition using H1000. I mean groups averaging .75" at 100 yards. This is awesome out of a caliber this large. Over my chrony he exceeded 2900 fps by just a little. My suggestion is that if you buy a rifle I would stick with a Remington or Winchester. The Browning will weigh a little under 7 lbs. The Rem or Win will weigh 8 lbs. I would also opt for a muzzlebrake if you don't want to develop a flinch.