antique guy: No...I don't think you'll hear any complaints, either ! I like 350 grain bullets too. Particularly the 350 grain, Barnes all-copper X-type bullet. Good accuracy and terminal performance on game. Have used it in a variety to scenarios. If you can get them, Hawk Bullets list a really nice jacketed soft point bullet that also delivers. One bullet that I found surprisingly good(I shoot more of these than any other), was the 350 grain Hornady jsp. This round-nosed bullet also performs well. Have taken everything from white-tailed deer to moose with all three. Powder of choice being Reloder 7, in all cases. There are other good powders that work equally well. My rifle simply prefers that combination, with that bullet weight.
Don't want to wander too far off the OP's original thread but, the .303 British is a pretty capable cartridge, too. Have likewise taken all manner of game with one. My first "big game" rifle being a modified sporter, based on a 1917 BSA , No1 Mk3 service rifle.. Paid something like 15 bucks for it. This was in the early 1960's. Gifted the rifle to a nephew for his first hunting rifle, some years ago. Still going strong and putting venison on the table.
The OP can too, once he gets the Lee Loader's powder scoop sorted out.