The equipment that I use to time locks consists of a computer and interface made to scientifically measure time in a high school or college physics lab. It has the ability to measure times to the nearest ten thousandths of a second. The lock is fired electrically, and time is measured until a flash in the pan triggers a photoelectric cell, stopping the clock.

What's the best load for my 45 cal flintlock?

Flintlock Timing by Larry Pletcher | Muzzle Blasts Archives 1990

Flintlock tips for the field from Ramshackle Homestead with Keith and Jen