I think I stated this in an earlier post but..... The gun shot 305FPS with .23 BB's and green gas (or propane) when I first got it. When the velocity started to drop off I switched to red gas and the velocity went back up to 350 with .23's but it keeps droping. I am now getting only 275 FPS using .20's.... Something is causing this but I have tried all the obvious like leaking mag's dirty barrel, seals, etc.
oops! Sorry, that "earlier post was on the Airsoft Mechanics BB. My mistake
Copy of that ASM post
OK here goes: HFC M190 Special Forces edition, one year old, maybe 750 rounds fired, never abused, stronger hammer spring installed. started it on propane, it shot 305 FPS W/.23 BB's. Velocity has been dropping steadily since new. Normal maint. performed: clean barrel,lube gun W/ sylicone, add sylicone to gas,.. Switched to Red gas about 3oo rounds ago because propane was only giving me about 250FPS. When I first switched it went back up but now using .20's I am only getting about 275FPS