Your results seem similar to the Richards Custom and other similar rifles.
Another board offers drop-in barrels from Pac-nor for Savage and Remington actions. Most do go with the 45 to shoot sabotless bullets.
I prefer to shoot sabots since I can shoot bullets with much higher BC's, but sabotless does offer a much cheaper cost per shot, and almost automatic accuracy....assuming the wind does not kill the shot
PS while I do like the 45 for my sabots I would definitely go back to my Gibbs 505 barrel but with a 10 twist to shoot the 300 grain SMK's and the soon to be Berger 300 grainers! I can barely get the 250 grain Accubonds stable with my 14 twist!