The Crosman 600 can be fitted with a longer inner barrel very easily so that you can attach a silencer, and with the longer barrel can give 6 ft.lbs.
PETE.
As shown in PISTOLS PICCY
ULTIMATE KING RATTY ::.22 SMK QB78DL HYBRID::+QB78 D/L .25 Cal ::850 AIRMAGNUM::PISTOLS- :22 Cal Weihrauch HW80K Tactical::RAM 68 :-)