Those 100 dollar, or around there, jobs are pretty much junk. I've gone through 4 of 'em. Well, only three. . . Shot all of them. Kinda by mistake but nevertheless they still got shot.
If you're gonna bank on what the chrono says you're gonna have to pony up some bucks.
Around 500 or so. . .
However, a chrono is not absolutely necessary. Darn handy but not a deal breaker if ya don't have one.
The magnetic on that mounts on the muzzle is the current cats meow.
However, technology moves on. There will be a doppler radar chrono on the market later this year.
Less than $500.00 (so far)
This one will me way more than handy.
If a couple of fellas get one each determination of bc will be come a piece of cake.
My Chrony hardly ever gets used anymore.