If economy is a priority, 357mag is the way to go.

It’s very accurate, particularly with a light charge which means Powder goes a long way - I get just shy of 1500 rounds out of a 0.5kg tub of N320. It’s also the easiest to acquire components for.

I’m probably going to be berated for this but in my experience Lee equipment is relatively cheap for a reason, you get what you pay for. The kit is “ok” or is inconsistent or breaks easily - their 38-55 dies for instance apart from the sizing die are actually 375H&H dies and the seating die shaves lead off the side of heads affecting their accuracy! The ones I acquired now are relegated to backup and replaced by a decent brand which do the job correctly.

I would recommend investing in a better brand of reloading gear as it is better quality, particularly the dies. RCBS, Redding of Lyman all being excellent - the RCBS Cowboy dies being the best (imho) on the market for loading Lead heads. If progressive presses are the order of the day you cannot go wrong investing in a Dillon 550 or 650 set-up, they’re the best on the market with what is probably the most consistent Auto Powder throwing system you can get.

Andy