John: I haven't had any experience with a 375 Winchester, but I have had a BLR in .358 for over 20 years. I doubt if you will notice any real-world performance difference between the two, though I noticed from Chuck Hawks' recoil table that the .358 has a little more bite for your shoulder. My BLR likes 47.0 grains of IMR3031 behind the 180 gr. Speer Flat Point for the whitetails here back east - note that this isn't a hot load. If you do a search of this forum, you will find some posts concerning the .358 - it seems to be pretty popular with the members of this forum, despite its lack of popularity in the marketplace. Here is a link to a recent posting on this site:

http://www.accuratereloading.com/ubbthreads/showflat.php?Cat=&Number=469299&page=3&view=collapsed&sb=5&o=21&fpart=1

Hope you enjoy it - pagris