Yes. I built mine with two boards about ten inches apart. Hole bored through both. You only need one. Boards were 90 degrees to flight path of load. Shot passes through the hole. They limited the amount of non shot stuff which passes over the chrono screens. Without them the mass took too long and gave results which were extremely slow. Shot might have been 1100 fps but because of the entire train it was recorded as 820 fps. With the baffle I got just under 1075 fps. You need to figure adjustment in velocity because the screens are moved away from the muzzle. I love shooting black powder shells. I get a lot of WHAT the HECK was that questions.
