Take a gun chambered in 41 long colt. (if you know the 41 colt you know that the bullet and bore dia were mismatched) bore dia is about .401. Bullet dia (inside lubed) is .386. The heeled bullet is about .405. What kind of barrel should one be looking for to sleeve the barrel to shoot an inside lubed bullet? Im my research i cant find a common barrel dia that is around the .380 dia and would grab a .386 slug properly.