I do. If I'm working with something new, at home I load up the starting point - rounds. Drive to the range. If that load looks like it has good potential, I use a Lee Hand Loader to see if the load is going to meet my criteria.
I don't even have a press yet! The classic Lee Loader is the only thing I build loads with, so far. I have only taken it to the range once so far but
iIt is fun to make loads and shoot them on the spot!
I got one of those lee hand presses .i used it for reloading in RV for many years . I was working around the USA and wanted to shoot so I never let no ammo slow me down just made me down. told wife if RV even catches fire run till you can run any more . Had propane primmer and powder in there.
I don't. Might be a good idea for some folks but for me there are to many distractions at the range for me to feel comfortable working up test loads. I only work up test loads at my bench where I can give my undivided attention to what I'm doing. I load a few, label them, and then go test them out.
Note of caution:
I've read that loads immediately loaded and shot should be "wallowed" around a bit before loading and firing. Some folks have had a bad experience with "fresh" loads. Seemed when research was done jostling them around some, like in a trip from bench to range, cleared up the problem. Don't know from personal experience but this is what I've read. And all you folks from the south know what "wallowed" is.
I would love to have a mobile set up that I could use at the range. Right now, the range is about 15 miles from my house, so running out of ammo, driving home, loading up and driving back gets tiresome and expensive. I acutally thought about using a 3 hole turret press on a small card table and tossing that in the back of the truck to take with me, but abandoned the idea as too much of a headache to worry with.