These blow tubes that are manufactured here at Buffalo Arms, are an absolute must when shooting straight Black Powder Cartridge loads. When shooting these types of loads, you need to soften the fouling after each shot. You do this by inserting the cartridge end into your chamber, and gently blowing through the clear tubing end. Look for moisture in the clear tubing, and you will be able to tell whether you are getting any moisture into the barrel. With the 12" tube you will be able to keep an eye on conditions, and /or adjust your sights all while softening your fouling.