If you can, try and stay away from the jacketed stuff. Cast will shoot just fine, and as fast as you can drive it from the 38-55 case anyway, one of the reasons I got my barrel.
I did what others had been doing before me and poosting about, simply running laoded cases back into the sizing die enough to make it chamber. I find that sizing just the length of the bullet is enough, I set my die up so it only screws into the press about 1/4", don't do anything you ain't got to do.
I'm not sure what gives with NEF about their chambers and bores, but a 375 chamber and a 379 bore seems to be the norm for the 38-55. Don't give up on it, these are good shooters, so I've read and experienced. Do a search over at the AR cast bullets forum, there is an exellent thread on the 38-55 Handi and these problems and the resizing die resolution.