Richard,
I got my .379" bullets from Boer Bullets, but he sold his swaging gear to another member here, dunno if he's selling bullets tho, but there is another fella that makes .378" bullets that he says work fine in .379" bores, they're soft enough to bump up, the link is in the H&R FAQs hiding in plain sight, he wasn't making them when I needed em due to family obligations(new baby), but has since started up again, sent me an email last summer, IIRC.
Tim
http://custombullets.com/