My current chronograph is from Caldwell. I use it mainly for verification on the consistency of velocities. I picked this one as it syncs via Bluetooth to my smart phone. I can observe each shot on the phone. The phone app allows me to save groups of shots into a file. It allows for deleting of a problem round It gives me my spread and SD. I can also attach a photo of my group to the file. I can record as many rounds as I wish to a file
Here is a screen shot of one of the files from my phone