You'll find the folks at Dillon mighty helpful. I got my 550b at an estate sale for free after I sold off most of the other stuff I bought at the estate sale. Called Dillon for an instruction book and spare parts and guidance in setting it up and it ran like a top first try.
I also load 200gn LSWC but I use 5.0gn Bullseye and CCI 300 large pistol primers in a 4.5"bbl. There is little fouling and the recoil is easy to handle. Also, Bullseye being a very fast burning powder there is almost no flash at night. I was using AA#7 to begin with and it lit up the entire range at night like a flash bulb.
Gerry