Hey Daryl,

We used Douglas button rifled 1 1/4" full blanks 26" long. That way we could turn it to the dimensions we needed. The gun was 12ga. so we reammed the chamber to square it up and leave a shoulder at the forcing cone. Then pulled a straight reammer through the bores to true them at the muzzles. If you turn the bbls. on centers, you'll want extra length to trim off the ends.