I finally got to try out my new ProChrono with the Bluetooth attachment this past Monday after work. I was a little skittish because I have a scope on my AR15 that is about 3 inches over the bore so I knew that the bullet should be at most three inches below POA at fifteen yards. To find out where the bullet would pass through and not wanting to destroy my new chrono with the first shot, I posted a target at the fifteen yard line, drew a bead through the scope on the center of the target and fired a shot. Sure enough, the bullet hole was just about three inches lower than the POA.
Knowing now where the bullet would pass through the chrono, I set it up at 15 yards, turned on the chrono and the Bluetooth and shot through it…immediately a FPS reading came up on the smartphone…hey, it works!
I ended up putting twenty rounds through the chrono and learned several things…I need to tighten up on my reloading regimen…the FPS spread over 20 shots was 277. Not real good. In defense of myself though, I know that these rounds have been around for God knows how long and I never really loaded for accuracy in the FPS department because until now, I had no way of measuring the speed of the bullet. The other thing I learned is that a wide FPS spread doesn’t seem to affect accuracy, at least out to 100 yards (maximum length of the range), as the same random rounds I was using were punching the two inch dot at that distance.
I have 20 rounds that I am going to load up, already sorted, paying special attention to head stamp, length, weight, primers, etc and see if I can tighten that FPS spread up a bit (or a lot).
All in all, it worked very well and very easy to use.