Back in the Mid-90s I went to the gun show at the NEC. At one "have a go" stand (near the airgun range) there was a dude demonstrating an electronic training aid. There was this fairly bulky assembly you clipped under the barrel of an unloaded gun. The device then detected the vibration of the hammer dropping and "fired" a LASER beam at an electronic target. The target contained a set of photo-receptors and relayed the "impact point" to a PC, which recorded the positions of the shots in the string & could print out your group along with a string of numbers such as group diameter, X and Y dimension of the group, score etc. At the time I didn't give it any further thought, as I was having too much fun with airguns. I'm thinking about it again now. And I have a question for those who may have kept their ears closer to the ground in the last few years. Has this technology been developed into less clunky form? Is it affordable? Could you mount the sender onto a de-ac pistol? I'd heard that post-95 de-acs have badly bugerred-up trigger ramps, assuming the hammer drops at all.