The Mk-III doesn't have a printer so can't use that test.

The real questions are - at what point (voltage) do false readings begin? How many of the previous years and years of testing is invalid? Can this chrono be trusted in the future?

The experience with the .243 was obvious. One of the reasons I shoot .22 for control is to catch obvious malfunctions but this time the 22's were in their normal fps ballpark - I will assume because they are the first thing I always test, the battery may have had enough surface juice when first turned on.

I suppose I will have to check voltage every time and plan on keeping fresh batteries on hand and do one 22 test at the end of each session..