I can't count the rounds of shotgun ammunition I've loaded over the years. For some reason, it's the one loaded round I don't keep a record of, and that's probably because it's a love/hate relationship. We go through many thousands of rounds of a special load for shooting steel targets, and a like load in factory ammunition is the Winchester AA Lite, which is expensive.
I do my loading with a MEC 9000GE, which is run by an electric motor. You put the hull on the carrier, add a wad and push the two buttons at the same time and a loaded round is ejected out the back. Simple, right? Except for when the hull wobbles, and the decapping rod goes through the side of the hull, or the wad fingers catch the side of the hull and collapse it. That causes shot to go everywhere. Oh, and sometimes the new primer doesn't land correctly and gets mashed when seating, or lands upside down, both of which cause powder to spill and mess up the whole procedure.
Whenever something goes wrong, be sure to check all the stations to make sure what was supposed to happen at each one actually happened. Bloopers are embarrassing........
No matter how careful you are when loading shotgun shells, shot and powder are going to eventually end up where you don't want them. It's a rule. I mostly load #8 and 7 1/2 shot, and it's just the right size to get down into the carrier and cause problems. Small forceps work well for picking them out of where your fingers can't reach... I've yet to find a way to keep shot off the floor, too. I didn't know lead shot was magnetic, and that concrete was a lead magnet.............
I dread loading shotgun shells, which reminds me that I've got to load more, since our stock is down to about 10 boxes, which won't last long. I normally load in batches of 3,000 rounds, mainly because I consider it a chore, rather than a labor of love like reloading metallic cartridges, so once I start, I get enough done that I won't have to do it again for awhile.
The other thing about shotgun loading is the amount of room the components take up. Shotgun hulls are bulky, and a case of 5,000 wads takes up a lot of room. Bags of shot are heavy, and getting more expensive all the time. I got lucky and bought a ton of shot a couple of years ago for $23.00 a bag, and I've still got about 500 pounds of it left. When that's gone, I don't know what I'll do, since I'm not about to pay what they want for shot in the retail outlets, which was $40 to $50 a bag the last time I looked.
Did I mention I don't really like loading shotgun shells? In case I didn't say it, I DON'T LIKE LOADING SHOTGUN SHELLS!!
Hope this helps.
Fred