You are way off base. Minimum rifle barrel length 16". Minimum shotgun barrel length 18". Both cases the firearm has to be over 26" long total.i thought that the barrel minimum was 14.7" ?or the oal of 26" am i off base here?
The way to measure barrels is to close the action. Drop a dowel down the barrel till it hits the bolt face. Mark the dowel right where it exits the longest part that is permanently attached to the barrel. Most folks choose to be 1/4" or so longer then minimum just so there is no question. To measure OAL open or extend the stock (if that is an option) lay the butt flat on the floor. Measure from the floor to the end of the barrel (or anything permanently attached).