I want to know which one is a better choice a 5-15-40 or 5-15-50. I have a 300. rem ultra mag and i hunt deer and plan on elk and moose.
A poll was taken on this site many months ago and I believe that the average shot on game was well under 200 yards.
A 300 Ultra mag is essentially for three purposes: 1) to kill large - I mean really large - game at closer ranges, 2) kill average sized game at really LONG ranges, and 3) just something to have that really makes a big BOOM. Unfortunately, most people have bought the Ultra Mags for the third reason, and I myself fall partly into that category.
However, believing that there is at least a little truth in all of the magazine hype, the Ultra Mags are indeed capable of taking really long shots - that is if YOU are capable of taking such long shots.
I say this because, if you are capable of shooting a deer at 400 yards with the Ultra, then I don't think that a 15x scope will too much. Granted, the biggest "if" is if you can shoot that far.
Under normal circumstances, your standard 3x-9x magnification is all that you need, and, as such, anything more than 12x is too much. Then again, for deer hunting, all you really truly need is .270 or 30-06 and, as such, anything more than that, like an Ultra Mag, is too much.
As for objective size, that being 40 or 50mm, please, please, please understand that a 40mm objective with excellent optics is better than a 50mm objective with just good optics. As such, please don't think that "bigger" is always better. Bigger is only "better" when the optics are the same. As such, it would be much better if you got, say, a 4200 with 40mm objectives, than a 3200 with 50mm objectives.
Zachary