I bough the paid version. Will not reliably detect dry fire shots with a striker-fired pistol. It will however, pick up the sound of drawing from a Kydex holster. I played with the sensitivity settings. Just doesn’t work. All I wanted to do is practice single-shot draws from concealment. This app will not work for that purpose.
Developer, if you would utilize the mic on an Apple watch, it may solve this issue. Just a thought. As the app is (Sept 2022), it is not worth paying for. $3.00 down the drain.
I did not test during live fire, and the app may work fine for that. However, I have a real shot timer for range work. Disappointing.