Sticky M9 blowback chamber on a KJW? Lack of hopup on it also?

[ancorp]

Bought a beater KJW M9 a while back, has always been having one small problem.The loading nozzle/blowback chamber/cylinder or whatever you'd like to call it - sticks forward at times. Taking it apart showed mangled blowback springs which I swapped out for new KA ones. Still the problem is there. Looks like there is too much friction between the rubber piston head and the cylinder. Tried AI silicone oil, helped a little but not that much. If I oil it and go to a CQB game, by the end it usually starts to lock the slide on some shots. But generally the force of the blowback snaps the loading nozzle into place. Sometimes it doesn't:



Perhaps a new piston head is in order?

Another issue - feels like there is no hopup present. I own 3 KJW M9s, and all 3 do this. They shoot at a good velocity (300fps+), hit hard, but the BBs drop fast. Even with .2g it doesn't fly straight at all, have to lob the BBs. (Don't see a hopup adjustment anywhere, I assume all mine have fixed hopup, their hop is set for .2s from factory). The rubbers look fine on all of them, one of the M9s looks almost brand new.

Any tips?
Thanks,
Alex

[BorisKarloff]

I own two WE m9's which are effectively identical.

First off I'm curious if you fixed the problem with the sticky blowback assembly as i am experiencing the same problems in both mine. Secondly if you haven't figured it out already there is a hop up adjust, you just need to field strip, then remove the innerbarrel/hop assembly from the outer barrel, and once you do that you will see a small flat head screw on top of the inner barrel / hop up frame. Tighten or loosen that screw. The screw loosened off on one of mine and thus i effectively had no hop up whatsoever and bb's would fall like rocks.

Am really trying hard to figure out how to get the blowback assembly to move more cleanly, dunno why its so damn sticky n designed with so much friction.