Started with a Savage Axis in 223, swapped the bolt head and obviously the barrel.
Went with a 1:16 barrel as I want to work with heavy for caliber cast bullets sub and supersonic.
Plan to run a box or two of factory stuff through to check function, break it in a little, get scope zeroed etc.
Will probably purchase a few different styles/weights of cast bullets to get in the ballpark before I invest in moulds.