Yay! Woah you got it right I believe! You should have - Hi-Capa God Certified - Brian
I think it is the Loading nozzle rubbing against the rubber O ring creating a lot of friction. And yes the Loading Nozzle tips also appears to have some scratch marks. So yes it must be the Mismatched Outer Barrel and to TM Plastic Slide.
Too bad I did not get the Plastic outer barrel slide with it
(2nd Owner from Kamatokai)
So I guess I need a new Blowback unit and revert back to stock outer barrel slide?