Long throats seem to like long bullets. I have four rifles in .300 Win. Mag., three Ruger #1's and a Winchester M70. Two bullets work the best in all four rifle. Either the Speer Hot Core or Nosler Partition in 200 grain weight will shoot sub MOA in those rifles. Both bullets push close to 2900 FPS but the powder I use is no longer available so unless you have some Winchester magnum Rifle (WMR) my data won't help.
I guess what I'm saying is try working with one of the 200 gr. bullets. You might be pleasantly surprised.
Paul B.
