Well, there is allways room for one more gun. The way you say possibly an Elk hunt in the future indicates to me that you may not be sure where
you Elk hunt if you go. If it is in Black Timber or thick stuff like the Pacific States, all cartridges mentioned would be fine. However, if it is more open like alot of country in the Mountain States, the 338 Federal would not be my choice, it is more of a Short to Medium range round in the bullet WEIGHTS that you would use for Elk & your existing 30-06 would be much better for that job & the other 338 rounds more so. For example, the Sectional Density of the 200 Gr. 338 is .250 & your vel. in a 338Fed. would be about 2,675 or Fact. 210 @ 2,630. The 30-06 with a good reload would be 2,650-2,700FPS with a 200 gr. with a Sec. Den. of .301 with a much, much higher BC, the difference after 300 yards in Energy, Vel., &
Trajectory would heavily favor the 06. And you can forget about getting any velocity with 225Gr. or heavier wt. bullets in the 338Fed. The factory 185TSX may be a good option, but your gun may or may not like it. I am not slaming the 338Fed & I have no need to do so, it's correct application is Short to Med. range. For the Pa. Black Bears, it or any cartridge mentioned would be great.
I like the 338-06 & the 338WM a lot & both have the right stuff & the 338-06 has enough boiler room even for the 250 Gr. but would be very, very
good for the 225 & under.
Mac, as I have said on previous occasions, that is a fine rifle. I like the fact that with the 26" barrel, you get VERY close to 338WM in the most common 24" tubes, & you get that performance with less powder & recoil.
Yet, because of the Single Shot action you have a compact rifle that is
about the same length as the shot action 338Fed would be & they are not in the same Horse Race. Yes, I am selling myself on this concept & it seems to be taking hold. :-)