I use 13 grains of Unique under the Lyman 314299 bullet unsized but lubed with a gas check. This is very close to a max load with this bullet according to the lyman manual. I have found these bullets are more accurate unsized than sized.
I have also found that one martine 303 and two No.4 rifles will cause the bullet to tumble with every cast bullet I have tried. All have bores larger than 0.314".