When I first started using a chrono to check my handgun loads, it wasn't long before I pulled a shot. I knew I did it the moment I pulled the trigger. I fully expected to look down and see a hole in my chrono, but somehow the bullet missed. I considered myself to be very lucky. From that point on, I started using a rest whenever using a chrono, to help prevent hitting the chrono, and to take out some of the human equation when checking for accuracy. I've since put well over 1000 shot groups across my chrono and have not hit it - yet.