I have had that same Lyman trimmer for years, but mine has been a bit of a disappointment. I simply never got really consistent trim lengths with it no matter what I did.
I never was able to figure out what the problem was, despite its' apparent simplicity, and went back to using the simple Lee piloted cutters for case length trimming. PERFECT every time, (except for an old one with an aluminum pilot that eventually got chewed up at the end by the cutter, in effect shortening the trim length.) The newer ones are hard SS, and haven't caused any problems whatsoever.)
I do have the neck-turning head system and pilots for the Lyman trimmer and that is an excellent performer, however. So I use it for that, with great results. The hand crank works better than the power adaptor for neck-turning, BTW.