Hey Troy, nice gun. Tuning wise the old way Mike slowed the speed down was NOT by hammer spring tension, but by tuning port screw lengths. He would have a tuning port screw (the 8/32 or 10/32 in the swinging breech arm) for each benchrest class. IE; lv, hv, etc. Once the hammer tension spring tension was set, the tuning port screw does the rest. So, that takes some time and a hand file, dremel tool or bench grinder, and a hand full of screws that are slightly longer than what you need them, because you will be grinding them down little by little to get to the speeds you want for each class. I am sure Mike N. or Rod as you mentioned above, may chime in with further info. Old school method, and it may still apply on his new guns?, was to turn the tuning port screw back out enough, until it provided no restriction. Shoot pellets over the chrono and screw in hammer tension until it hits top speed, whatever that may be. Once there, back it off an 1/8 turn at a time until you lose about 20-30 fps velocity. At that point the hammer tension is set and max velocity your gun will be able to shoot (depending on reg pressure) . Then, screw the tuning port screw back in til its tight (this would be your original screw thats already ground to length). Whatever that speed is, if it works, can be set slower with a longer screw, or sped back up with a shorter screw. You will have to spend time and pellets over the chrono to get it right, but its easy to do. Then keep your TP screws separated so you know which one is for whatever class. Hope that helps....im sure someone else will chime in, but this is how I have always tuned my FT Thomas and helped other tune theirs.................... BC