A couple of things with chronos. Yes you can't get muzzle blast to close to chrono causing errors and misreadings. Also sunny vs cloudy days make a difference. Cloudy days have the best results for me not using diffusers. Cloudy days give me the most accurate readings. On sunny days you can get shadows from the bullet across the chrono. So on sunny days I use different methods to block all shadows. I'll use the diffusers on sunny days. This seems to work well for me.
Adams
