i do have a 450 400 double,then the 470,it appears the 577 0r 600 would fill my gap on the low end i have a 9.3x74R so the lower end is filled.i am just facinated with doubles and i am learning alot here thanks to all here.i have a good 30-40 years left to collect and i wat to end with a 700 to be mine.i have to dream and aim high,dreams do come true