I do not own a shot timer and am wondering if anyone has one on their phone that's good. I went on Google Play but am looking for recommendations.

I am running a rifle drill tomorrow with a friend and he doesn't have a timer either.
Thanks in advance.

I have an app called Splits on my Android phone and tablet. It's been working fine. I wouldn't try running a match with it but for informal range use it's OK.

My experience with several apps is that they don't work very well and you're better off using a stopwatch unless you NEED a very fine level of timing. Generally you're going to be with less than one second just timing it. Plenty accurate for many drills, not adequate for, say, a Bill Drill.

The issues I have seen are unreliable shot detection, detecting shots as multiples, detecting shooters in other bays, etc. I've also found the start and especially par beeps are inadequate. Most of my experience is running the timer for myself, so your mileage may vary if you are timing the other shooter and vice-versa.

It won't do you any good tomorrow, but I would suggest that anybody with an interest in metrics just bite the bullet and buy a timer. You'll use it nearly every time you go to the range.