Anybody know anything about them?
I know it's a .221 Fireball opened up to accept a 6.5 mm bullet, but finding out such things as bullet weights and the associated ballistics is not super-quick. Seems like you can find a range of weights and velocities, but no real info. Not even the parent company, SSK Industries, really has good information.
I'm thinking this would be a need little chambering for an AR-15 carbine, and good in the 100-200 yd. range in either supersonic or subsonic form. Subsonic would be academic, as the main advantage (using a silencer) is not as easy here in my county. Sheriff won't approve 'em.