Having recently completed my stock modifications (http://www.gatewaytoairguns.org/GTA/index.php/topic,37988.0.html) I've been looking for a better way to evaluate the multitude of combinations to find the best setup, pellet/tuner/FPS.... Found this TDS program at http://ontargetshooting.com/ I've also been looking for one of the old Beeman pellet sizers but haven't had any luck. Then I found this 4.52 pellet sizer on Ebay from the UK I washed, lubed, and sized 100 of each AA 10.34, JSB 10.34, and JSB 8.4 and set out to shoot some groups to try out the TDS Program. While this morning wasn't exactly premium group shooting conditions, 38F with switching winds 8-12 mph (at times my two wind flags were facing opposite directions with tails straight out ), I gave it a whirl anyhow. I shot 10, 5-shot groups of each pellet using a target printed from the TDS Program. I then scanned the target and used the program to analyze the groups. To give you an idea of what the program does I've attached the data printouts for the JSBH (10.34) and JSBL (8.4). Given the wind conditions I was surprised to see the JSB 8.4 edging out the 10.34.Winds are dying down a bit now so think I'll try out a few more groups.