HI TOM I see many like air gunters and BOB 0 using slugs in fx in 22 caliber and very good results , I only make 36 and 30 gr slugs in 22 , I dont think the impact or crown can shoot them , currently with the power and barrel twist but I did see a new impact which seems to be like a total slug machine with alot more power out of box , I do not think fx released slug barrels in anything but 22 but i may be wrong