I also use a Rock Chucker that I bought in the early 70's. The too are a great machine and would probably be the best to squeeze out the lats 1/8 inch of accuracy. But, I am wanting to experiment with the progressives to compare the results; actually, I enjoy shooting and want the volume provided by these machines. I must say, thus far, I am really pleased with the results of the Dillon progressives; the accuracy of the powder and case dimensions are excellent (surprising consistent). I own two RL1050's and an S1050, and I am still in the process of tuning the last RL1050, that one, is an early production nickle plated machine; it currently is the most impressive of the lot. I cycling seems quite a bit smoother on the nickel plated machine than either of the other 1050's that are ductile iron.
I also have an RL550 on the bench with a very low round count (less than 2000) if anyone is interested. That being said, I will keep the 30+ year old rock chucker! After all, there are some things that are never outdated; does anyone own a 1964 Corvette split window coop that they want to sell?
Don