OP, I may be presumptuous here but IMHO you are forgetting the advantages of the 338 Federal. The bullet diameter is part of a substantial gain in opening a larger hole.
I made up a 338-08 on a Mauser 98 action many years ago. I removed some of the already slight taper from the case and increased the shoulder angle as well to 40 degrees. I had picked up a custom reamer that was made for another cartridge with very similar dimensions I also had a take off barrel from the rifle that had been chambered for the wildcat cartridge which was a blown out 30.06 called the 338 Jordan.
The shoulder had been pushed forward so that the neck was slightly less than one caliber in length. This substantially increased powder capacity and actually made a noticeable difference over the standard 338-06. The thing was, the felt recoil from this cartridge in a Ruger No 1 was equivalent to the 338 Win Mag. The fellow that made up the reamer and built the rifle was Harry Nicholson who now resides in a little town called Tappen. He used to have a gunshop in Chilliwack BC.
OK, The main difference between the cases is the Federal has a 2.5 degree body taper but a longer shoulder. That's it for all intents and purposes.
I tried all sorts of different weights/shapes/manufacturers bullets in that rifle to find what was a good all around bullet for my purposes. I finally settled on the 200 grain Speer flat base spire point with about 2600fps from my rifle. I used 50.0 grains of W748 over CCI 250 magnum primers in fireformed Remington cases. This is a good recipe for my rifle and is deadly on Deer/Black Bears/Elk and Moose out to 300 yards. The bullet opens reliably out to that range and up close.
This bullet may not be suitable for your purposes but with that cartridge which wasn't designed for long range shooting it works extremely well. The trajectory isn't as parabolic as you might think either.
The Barnes offerings look pretty promising and when I've finally used up what I have left of the Speers, which are already proven, I will likely switch to one of them. I like flat base bullets in this cartridge because they don't take up much powder space and they seem to shoot better in my Gaillard barrel.
Have you tried polishing the ways and feed ramp on your receiver to enable better feeding? Often the fee ramps are to steep or the ways are to sharp. Just a thought.
