I have had a Dillon 550 for about 20yrs and love it! The big difference between the 550 -750 is 4 stations on the 550 and 5 stations on the 750! And the auto indexing feature on the 750(which I don't like). The price of the 750 is much higher and the caliber change kits are also higher than the 550. 500rds on the 550 is a couple hours for me, with everything ready to go before starting, no auto case feed! I have 4 Primer pick up tubes for each size, 2 powder drops(one w/small bar and one w/large bar), and a block w/powder drop tube for each caliber I load.

jcelect