Actually the 7mm rem mag is still the top dog when it comes to popularity for magnums in NA according to sales. IMHO one reason why the other "7 mags" haven't fairedas well...this includes the WSM, RUM of today. They are also good but the rem mag works very well with 140 to 175gr bullets for NA big game animals (other then big bears). The only real need for the bigger 7 carts is LR and a flatter trajectory, however for most it unharnessed potential thus the rem mag is pretty appealing. Split hairs all you wantbut IME the 300wm does nothing the 7 RM can't. Personally wouldn't want a 300wm for big bears but I guess i'd rather have a 220 gr in a 300wm then 175gr in a .284 if those where my only choices when hunting griz country.

In terms of the TSX, I have plowed the 140gr through both shoulders of bull moose and single shoulders of elk.A++++++++ forthis application but I also am not a real fan of itfor deer sized. I keep going back to loading 150gr NBT's, these are scary accurate, produce top velocity/low fouling, excellent wound channelsand never needed a second on countless canadian whitetail/mulies harvest. The longest being a double shoulder DRT 478yard shot but have taken them throughthe shoulders at less then 100 as well(wound channel is a tad bit larger then one would see out a little farther though).

I have not used the XP3 can't comment.

I have used Nosler accubond's and put a 160 thru& thru both a bull moose and bull elk, they worked well for deer for me. I have witnessed the 154gr IBdoing well on deer through moose as well in the rem mag. 2 newer bond polymers that i'duse for lope to moose in a 7mm rem mag.

However ifI were looking for 1 load for all the first i'd try would be the Nosler Part. It just works. If it failed to produce the accuracyI wantedI'd move to the others. Only reasoni don't use it in my current rem mag today, previously I did and0 complaints.

If willing to shoot more then one load Barnes TSX for elk/moose/bears and something less robust for antelope and deer. It takes me a matter of some fine tuning & a couple groups to switch over between these loads. A minor hassle to some butI look at it as anotherexcuse to go to shoot...all good

Good luck