hello, i just purchaced a very nice double barrel shotgun and have the plan to make a nice short barrel unit out of it. before i can i know i must file the appropriate form 1. i see that number 4 on the form about the description, letter e length of barrel, and then letter f overall length what should i measure to fill in that part? if i was going to cut the barrel to 11.25 inches i see that part but what about the overall length? just get an idea of just about how long overall? kinda stupid question i guess. i have filed form one's before for suppressors but not for this so i dont want to screw up! thanks!!