Sorry in advance for the longish post.
In spite of the too warm weather, I setup my gear on my patio, got my industrial fan to cool me and blow the smoke away, and started casting .40's yesterday.
This was my first time using LEE 6 cavity aluminum molds (and my first time casting .40's) and I have to say, I'm impressed. I'm STILL using my rusty 35+ year old RCBS promelt furnace. In the past, using steel Lyman molds I really needed two molds, one to cool enough to let the sprue cool while I poured the next. The Lee cools enough in 4-5 seconds so I can knock of the sprue and quench (my first time trying it in larger production). I timed myself at 800+ per hour, easily equal to using two of my Lyman 4 cavity molds. I really doubt two molds will beat that especially with having to maintain adding a 2 lb. ingot to the pot every 70 rounds or so and fluxing.
Also the less weight of the 6 cavity aluminum compensates a bit for the Lyman steel weight and did not feel tired till about ~3k were in the water. Good thing the RCBS furnace has the mold support, I cant imagine using a furnace without one.
In the past I was very happy with the trench cut in my Lyman sprue cutter, but it caused a LOT more pot maintenance, the Lee was a lot better in that regard too.
So, right now my only Lee mold is the .40SWC, and yesterday I ordered a .40 TC. Once I PC the two styles I'll get to check the performance of the two styles and go from there in large production. Oh, I figure that the .40 is a good balance between the .45 and 150 grain 9's I cast regarding number of rounds I can produce from a pound of lead. It's not a bad bad getting nearly 30% more bullets per pound from my 220 grain .45's