My thoughts exactly LTLR. I like them both so bought them both. Figured that once I had them I would pick out the one I liked best and get rid of the other. Didn't happen.
I like them both. I do like shooting the .264 WM a bit better though and all joking aside that is one heck of a long range deer cartridge. I had a crap load of Sierra 142 MK's that I picked up in a trade and had used them to break in the barrel and then used them to work up a load with. The range I had been shooting at goes out to 1200 yds and with that bullet I had been able to keep them in a 10" circle on more than one occasion. Neck tension seems to be the key for accuracy at that range. I also found that if I dropped from using the Fed 215M primer and went to the Win mag primer my accuracy increased a bit. I am using Nosler Custom Brass and in my opinion it sucks. I'm up to 5 loadings and am getting loose primer pockets. The chamber has a short throat on this gun and I'm going to get that lengthened out a bit as I'm seating the bullet way down into the case. Seems to be a problem with Remington barrels and my bolt face has a .093 firing pin hole and the primers bleed back into the bolt face no matter what load I use so I'm going to see if Remington will fix this but if they won't I will get a PTG bolt and put that in when I re-barrel it when the barrel is shot out.
I used this load and bullet deer hunting this year and was totally amazed with what it did. Really tore that buck up inside. Hit him in the last rib and through the diaphragm and part of the liver. He did the high belly kick and hit the ground like a rug. Was able to get up on his front feet and was trying to crawl out of a gully when I hit him the second time and blew through the front elbow, lower chest and blew through the opposite front leg and with no front legs fell back into the gully. He was expired when I got too him. Not bad performance I'm thinking. That long heavy bullet has some punch. I think the .264WM will do well on Elk but I don't think I will use it for much past 800 on an elk although it would do the job and probably well.
The 7MM Rem mag I think with the heavier bullet 168 grain burgers seems to be as accurate as the .264 WM and maybe a bit better at the longer ranges and if I was going to try for an Elk out to 1000 I would probably take it just for the fact that it has a heavier bullet and might just punch though larger bone better if it has to.
One thing I did find though and that is 7MM Rem Mag brass is plentiful. The great part I learned is if you just run the 7MM Mag brass through the .264WM die you get a .264 Case and life is good. Wish it had the .264 head stamp but its easy for me to tell the difference between the two but I can see it would be possible for someone to screw that one up. Retumbo seemed to be the powder to use for either one as accuracy is good and velocity is good for both with low ES.