Well I got a chance to try the 300 grain sst hornady to day out of my 54 cal. thunderhawk.
All I have to say the performance was outstanding.I did switch the sabot to a red haevester 54 cal.with 100 grains of pyrodex select clover leaf groups at the 50 yard target.
A few time I shot the gun I thought I missed the target
NO way the bullet went threw the same hole in a 3 shot groupe
