My setup on my 550B for my precision AR is as follows:

1 - LEE collet neck sizing die in case there is a neck that is out of round, and it does happen when you store brass already prepped.

2 - powder die with funnel on top for pouting individual weighted charges from my Chargemaster 1500.

3 - LEE seating die marked with positions for different projectiles.

4 - LEE factory crimp die. I'll use it for different projectiles since I do my varmint loads on the same tool head. I've experimented a lil with each projectile and going some like a crimp and others don't.

I highly recommend AR Comp powder because it's extremely temp stable and produces insane consistency. It may not be the fastest velocity, but consistency beats all other things in my opinion.