Shot gun is probably the easiest to reload. I have not done it in a long time but my father started me probably at the age of 10 doing it. We both shot trap in a league so it was a 100 shells per week min for us. I've got a pair of units line the one pictured below. (12/20 gauge)
Pretty simple 5 stage loading press.
With practice you can load a few boxes in short order.
Speski OffRoad LTD, Cargo Solutions for Toyota 4x4's http://www.SpeskiOffRoad.com
"80 series, with a fridge"
1976 FJ40, Project with little progress.
2004 Starcraft 10RT