Buy a Lee 3 die set & an extra Lee seating/crimping die if you want to seat & crimp in separate stns. I like the Dillon dies in their progressives, but most all the dies work fine to one degree or another. The Lee lock rings are a ***** on the 550B tool head, replace those w/ the Dillon rings.
"Given adequate penetration, a larger diameter bullet will have an edge in wounding effectiveness. It will damage a blood vessel the smaller projectile barely misses. The larger permanent cavity may lead to faster blood loss. Although such an edge clearly exists, its significance cannot be quantified".