I dont own one but have shot one a little,,,if I was doing what you are fixing to get into I would have to try the Sightron SIII,,it has all the features you need to shoot the way you are going to have to,and make hits at the ranges the 338 LM is capable,
but I can not find where it lists how much adjustments it has,,
I know for fact with a 250 yard zero,you need 22 MOA to get to 1000 with the 300 gr bullet,,and 53 MOA to get to 1500,some of these bigger scope only have like 40 MOA of adjustments ,which just will not get it done,the Night Force 5.5-22x56 has 100 MOA and the Leupold Mark 4 has 100 and the Leupold LR/T has 90,,but you have to know that you will need a 20 and maybe a 40 MOA taper base to get the adjustments all the way down as low as possible to actually be able to use all your adjustments,
if you just put the scope on a regular base and the scope is centered and only has 40-50 Minutes of adjustment,you wont be able to actually use but half of your adjustments,,
I would try and find out how much adjustments the SIII has and if it is 75 MOA or more I would try this scope,,
http://swfa.com/Sightron-6-24x50-SIII-3 ... 48418.aspx