I have brand new pistons still in the original packaging for the Osprey and Octane silencers. I have a 13.5x1 LHM and a 14.5x1 LHM. You will have to Google specific fitment but I know that the 13.5x1 LHM will work on most european 9mm threaded barrels (I got it for a Sig P226) and the 14.5x1 LHM will fit .40 like the HK USP Tactical. These retail for $86 and cheapest I found them for was $69.