Heavi-shot patterns superbly with moderate chokes - up to about 1/4. With tighter chokes the patterns progressively deteriorate. The performance isn`t as good as with lead or bismuth but far superior to steel. Steel shot just isn`t compatible with fixed chokes unless those chokes are pretty open - I`ve just seen a Browning with car tire type bulges immediately behind both chokes ( 1/4 and 1/2.)