There's absolutely no reason to pick one over the other based on knockdown power or trajectory (IMHO, of course!). Both are excellent moose guns. Unless you plan to shoot at long distances and have difficulty judging distances at longer ranges. If you examine the balistics and power of the cartridges at, say, 50 - 200 yards, there is very little if any functional difference for killing a moose. The "boiler room" target presented by a moose is huge and a couple inches difference in trajectory at those ranges is way beyond meaningless. They are big animals, but aren't that hard to kill if you have a good shot at a reasonable range. Even a "heart shot"gives you about an 8+ inch circle.The difference in knock down power and/or bullet dropat those ranges is insignificant and the '06 has many shell/bullet options in a 180 grain while the 7 mag generally sends a 160 gr in common shells.Furthermore, if your gun will shoot well with one of the '06 high energy cartridges (mine won't), the '06 will essentially shoot the same or better as a 7mm mag in terms of trajectory and power at moose hunting ranges.

If you have difficulty judging 250 vs 300 yds, or haven't practiced shot placement at 300+ yds to compensate for drop, the impact point could be aproblem with your '06, slightly less so for the 7mm mag.

I've taken several moose at those (50 - 200) ranges with one killing shot with my '06, always aimed dead-on, always hitting well within the boiler room. The moose sometimes drop, sometimes walk 75 yds. just like whitetails do with the same gun and same shots. My friend has done the same with his 7 mag. Other friends havehad the same experience with .308 and .270. On a recent major hunt, with long time experienced and successful moose hunters our guns were: (3) 30-06; (1) 7 mm mag (1) .375 HH; (1) .308. The guy with the .375 told me the only reason he has it is that way back when, he had a 30-06 for moose hunting and it was lost or destroyed. He needed a gun quickly and found the .375, and has used it since. Not for it's additional power, but because it works and that's all he wants from a gun. The two moose killed, single shots each, were taken by an '06 and the .308. If I were to go after moose or other game which requires longer distances, I might buy a 7 mm mag just for it's flatter trajectory and marginally better foot/lbs at longer ranges with the lighter bullets. But to me the most improvement over an '06 would be a .30 mag, not a 7mm slug(which is closeto a .270). But for moose, sincerely, you should be shooting at ranges that are well within the "virtually equal" zone for both rifles.

Which do you like and shoot better- chose that one and don't give it another thought.Sight it in with a premium bullet that makes you confident in accuracy. Moose just aren't that hard to kill. They're hard to find, get to, and get a shot at in a place that makes recovery of the dead animal a reasonable chore. The size of them not only makes you want to shoot at a shorter distance (for quick-kill and recovery purposes), but also gives you a huge kill-zone target. Be careful to consider packing before shooting, and have fun!