The Shooters Chrony was and is a dreadful POS not worthy of spending a dime on.........
This ^^^^^
In my experience (and I bought my first of 3 Shooting Chronys in the early 1990s) you be way ahead by spending $100 or so for a ProChrono Pal.
Or the ProChrono DLX. I think it replaced the Digital and bluetooth's to your smartphone where you can store the bullet and velocities. Well worth the extra $25 IMO.
