[vindicareassassin]

Orange one has to be used with a zero trigger group.

Red one has to be used with either the standard or upgraded version of the standard trigger group. (what I got in mine )

No idea if the 'vacuum' is a reference to the air pressure holes on the face of the piston or not :-/ all they do is increase the pressure of the 'O'ring on the firing stroke ( better seal ) and reduces the suction on the cocking stroke.

Hope this helps

VA

 

[vindicareassassin]

The chrome thing with all the holes, thats a piston end, that is so if you already have an 3 part piston that doesn't already fit then all you do is unscrew the end, screw the supplied item on and away you go

If you've still got the stock item I would of thought the orange piston would work with it judging by the look of the release sear