Bountyhunter:

Simple expediency was the choice for the 9mm bbl; it came about out of finding a surplus sten bbl lying around the gun shop and it seemed like an afternoon project as it was already rifled and chambered and since there are always several hundred rounds of 9mm rattling around my car trunk. I got used to the 9mm in Vietnam and still like my Browning Hi-Power. Tendency to go with what you're good at and not have to carry another ammo mix. :-)
30carbine