I installed a Yo Dave kit on my 452 Varmint Thumbhole yesterday. It took about 20 minutes, the trigger creep was greatly reduced, and the trigger now breaks at 36 ounces.The trigger went from being one of the the worst triggers that I have used ,to being quite good. I used the blue spacer, and the heaviest spring in the kit. I found it easier to drill the peened end off of the pin, rather than try and force it through.I just ordered a second kit from Prophet River for a friends 452 American in 17Mach2.