I can't find where they sell the 9 cap for the Octane 45 anymore. Did you get it from the special run from Silencer Shop or did it happen on an Octane 9?
That was an Octane 45 with a 9mm cap shooting a G19. I bought it from Silencer Shop and they came in Silencerco packaging. I haven't seen any around for some time. Using an ablative makes a bigger difference, so I wouldn't get too hung up on the idea though. I just wished I heard somewhere to watch my rate of fire when using a piston.