A few days ago I was in Academy Sports and they had a good spread of 12 ga defensive rounds including
4 buck
ought
double ought
tripple ought
did not look at the 410 choices
i have used the lee load-all back in the 80's and it is a fine press.
You also might be able to check around and find some old used lee loaders in 410 and 12 ga but they are becoming collectors items in shotgun gauges so they are gettin high dollar.
As for the lee load-all----it is easy to use. I believe the lee load-all press was only offered in 12, 16, and 20 guage-------used lee loaders for shotshells are available on ebay.
http://cgi.ebay.com/1960s-LEE-LOADER-Re ... dZViewItem
http://cgi.ebay.com/Lee-Loader-410-Gaug ... dZViewItem
the 410 is sticker shock as it is "new"-----but used ones show up from time to time.
The MEC is considered top notch---but you have to buy different charge bars for different shot weights and have to buy different bushings for a change in powder charges------the lee includes these items for free.................
You also will have to have two dedicated presses with one for the 12 ga and one for the 410----i believe conversion is not possible on most models and cost prohibitive on others.
The problem with reloadin' shot shells nowadays is also ordering the components as you will pay out the wazuu in shippin' costs..........
If all you are going to do is just load say a couple of boxes a year of 4 buck and not bother to reload for bird hunting or clay bustin'------it might be cheaper to go the lee loader route...............
the lee loader is the only "non-press" way to reload shotshells that i know of.
if you are talking about taking a live round, un-crimpimg, pour out the bird shot, replace with wad and 4 buckshot, and re-crimping--------never tried it, but if i did, i would try candle wax to re-seal the crimp---but i'd study and research the heck out of it first for safety sake..........
rcbs also use to sell shotshell reloading dies for presses but i have not seen them in years.........
EDIT------just did some checking and rcb still builds the shotshell dies----but not in 410
https://www.gunaccessories.com/RCBS/ShotshellDies.asp