Not sure if sluggish is the right term. Well, this is about my almost brand new HP-BH. The trigger was pretty stiff so I switched to soft spring. With soft spring the trigger does not come back or if does, it comes back in slow motion. I applied tiny bit of lube but did not improve significantly; I took out the piston O ring, cleaned it nicely (no strong solvents, never put any before too) but to no avail. It kind of works if I keep the PSI to say 20 or above and control the air velocity using airbrush MAC valve. Bottom line is, it is working but not as a $200 airbrush should work. The airbrush code says it was manufactured in October 2018 so it is not like it was sitting in storage for years. Should I order a new piston O ring? I guess #94I1451 is the correct part number. If I must, from where should I order it? Coast airbrush? The problem is, the part costs just $4.5 but shipping is $10.00. I was wondering if I also order the valve piston? Maybe the valve piston is bit rough hence more friction?