I purchased a 6" stainless Python which had some timing problems last summer, and sent it to Colt for repair. I decided to have a factory tune on the gun, and Colt got it back to me in record time (Thank You, Colt!). Sadly, due to business schedules, I wasn't able to get out with it until day before yesterday. At that, I didn't have much time, as it was getting very close to dark by the time I was able to leave, but I needed to do something for stress relief, and I was itching to test the function of the Python, especially regarding primer sensitivity. The wind was blowing about 30 MPH, gusting to 45, so there wasn't much point in serious accuracy testing, and, since time was short, I didn't take any targets or stands, figuring I'd just shoot at whatever happened to be out at the "range" (a popular shooting spot a few miles out of town with a good backstop). The only "targets' available were a few soup and soft drink cans out at the 100 yard line. First, I fired about 20 reloads with CCI primers, and every one went bang, without flaw. Then, I fired about 20 factory rounds, again, flawless firing. It seems that the factory did exactly as I requested, a custom tune, but with enough oomph to fire any primers. Even though I wasn't testing accuracy, the winds were high and gusting, and I was shooting offhand at 100 yards, almost every round hit the target, both single and double action, and several cans were sent flying, with repeated shots doing the same, the other cans (weighted or stuck in the ground) just received holes in them - I can't wait to get out there with targets at more appropriate ranges and with enough time to really sort it out! So far, there is only one problem - now I am considering having factory tunes on my 4" Blue (bought new) and my Nickel 2.5" Python (1965 vintage). Thank you, Colt - Great Job!