I had no idea. I thought WE usually copied Western Arms and such. It makes sense though, Tokyo Marui makes the only PX-4 worth writing home about.
As for the Marui pistols, as of a couple of years ago they were all set up to run on HFC (duster gas); however, the PX-4 is supposed to be green gas ready. I'm with Hectic and Drake, I think your issue is elsewhere.
ďREALITY IS LIKE A STONE. TO MANY ITíS HARD AND COLD, THEY CANíT HUG IT OR EAT IT, IT ONLY FRUSTERATES THEM AND DOESNíT DO THEM MUCH GOOD. TO OTHERS ITíS STRONG AND DEPENDABLE, YOU CAN BUILD WITH IT, BUILD UPON IT, OR WORK WITH IT, ALSO USE IT TO SMASH PEOPLE IN THE FACE.Ē