Con. non gbb imho sucks. No slide movement, no recoil etc...
Nothing complicated using a gbb... Use duster for plastic slide and propane (with an adapter from Airsoft innovation) for a metal slide.
FYI i used propane in my WA infinity even if it had a plastic slide... never broke in over 3000bbs shot.
HellRanger 1969-2007 LRRP FOREVER
101e 506Pir Fox Company - SHTYK NOZH