Just took the converted Whisper .17 cal for a "test drive" Jay - absolutely great!!! ... First off, it's had a GRT-III trigger since day one, a BIG plus. It's kind of a limited test drive, I only put around 50-60 pellets through it, but a VERY nice improvement. - While I don't have a chrony, I know it's faster, by a good number, whatever that may be. It's takes a tad more effort to cock, but no problem at all. With the temp extremes we have here, and the ability to leave it cocked for hours etc. - a good choice. Accuracy was at least as good, maybe a tad better, but that's splitting hairs too much. - After the "short test drive", - I have no problem recommending the Nitro Piston conversion. - What it will be after 800 or 2000 shots I have no idea, but the same I hope.