I'm curious as to why a 338 Fed and not an UltraMag?
I have field dressed a few caribou that took 338WinMag out to 400 yards or so, and one moose that took a 300RSAUM at ~150. For all of the following I ass-u-me a good quality hunting bullet with proven expansion.
Personally I would like to put the off side shoulder in my freezer along with the rest of the animal. I am very happy with the Barnes X bullets, but they don't need to be moving at 2500+ fps. Plus I don't need all that recoil.
Also, when you turn around and find grizz tracks wider that you can reach with your pinkie and thumb that weren't there a minute ago when you were walking forward over that path; the gas bolt is a good feeling to go with the bad feeling of warm liquid running down your (my) leg.
20 round magazines are legal for hunters in Alaska. Certainly plenty of folks with tons more experience than me are doing fine with any number of cartridges based on .308. I honestly have (I'll go look) 8 boxes of bullets at .308 from Barnes TSX BT @168Gr up to Sierra 220 GR round nose, and I don't even own anything with a .308 bore.
That's a fine testament to "30 whatever" right there. I don't own any guns for it, I don't have any reloading dies for it, and I got $400 worth of bullets anyway.
For coastal Alaska trophy bear, salmon fed, squares over 8 feet, black or brown, sure .375H&H or better is a fine guideline. Good for white bear too if you are that lucky in the tag lottery.
For anything else in North America 300 whatever magnum is serious overkill. If you hit bone in the off side shoulder out to 200 yards or so you are wasting, easy, 20 pounds of perfectly good, and likely very expensive, meat. I am thinking of a caribou that would go probably 400 pounds on the hoof.
Even at 400 yards (the shooter claimed 600 yards) the exit wound from Nosler partition at 200Gr in 338WinMag is, well, messy. Boone and Crockett (mountain caribou) the animal went 397" on the antlers, too short for the rifle book, the bow book opens at 350", rifle at 400".
I encourage all y'all to wait for a double lung shot that leaves the off shoulder intact. At 200 yards 45-70 is (was) overkill on bison a century ago. The latest, greatest, fastest bullet is going to just wreck the off side if it hits any big bones. I just can't imagine using a 300WinMag on Whitetail even in Iowa on the corn fed examples. The way I hunt and trigger a 270 with a good quality expanding bullet is going to be plenty for any whitetail.
I also happen to be a fan of standing rib roasts with the little paper chef's hats on the end of each bone. I want a big fat bullet that destroys as little meat as possible, but expands enough to put the animal down humanely.
I know there is folks hunting heavy woods that want a big exit wound so they'll have a big blood trail. I am not going to argue with those folks. All I have to say is a .338 moving at 1900+ fps, properly placed, no blood trail is required. From what I have seen of caribou at 200-300# hoof out to 200 yards a lung shot with .300WinMag is the same as a sledge hammer between the eyes.
I also recall a survey by one of the magazines a few years ago. They asked how often hunters went to the range, what group size they claimed and at what range they had put down their last three whitetails. Running the stats on the responses they concluded most whitetail hunters would do fine packing a .357 magnum with a 4" barrel.
So all of that, plus .308NATO brass is plentiful and I can neck it up to .338Fed in one step. I have a gas bolt for heavy cover and a couple (Sako and Kimber so far) options for manual bolt. Even speed goat down in Wyoming I'll be able to deliver 180gr BT to 400 yards at 1900fps+, that's dinner right there. On the gas bolt I can load up heavy round nose for point blank
Jesus Christos moments.
I'll probably end up with a couple rifles in .308Win/ 7.62Nato, but it will be because the wood in the stock is so pretty.
M2c.