I am using the 8.5-25x50 MK4 w/TMR on my 338RUM pictured below, I also just received the brand spanking new MK4 M5 Locking Turret Leupy (6.5-20)which features mil/mil adjustments, FFP & 34mm tube. This scope is an absolute BEAST, I can't wait to get swapped out on my RUM.... Anyway, the adjustments on the MK4 are solid thus far, repeatability is a non-issue, works just fine. On your particular rig, I would probably recommend the 4.5-14 although, once bitten by the LRH bug, you are going to want to stretch it's legs a bit, the 6.5-20 is IMHO a more viable option once you start to get out to the 1k range... There are a lot of folks who use the 14x with good results at 1k, but I can't make myself comprehend why they limit the ability to "reel" that target/critter in... As the old saying goes..."when you need it & don't have it, you'll sing a different tune..."