The mini shells are only 1 3/4" long ( fired length ) ....vs the more typical 2 3/4" long....
To reload them, you'd have to make significant changes in a press for the height ...( they would resize and deprime in station 1 ok / but powder is going to drop too soon in station 2, ....and you'd have to find a short wad (the petals of the wad might be fine...but the plastic column in the middle of the wad is way too long ....and then your crimp stations ( crimp start,etc ...would all need adjustment ).
If you cut a hull to shorten it ....you lose the crimp / so that won't work unless you want to seal it with a cardboard card and wax....
All of which leads me to ....its a foolish idea....
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and why would you .....just reload and practice with standard 2 3/4" shells...don't make it more complicated than it needs to be, is my recommendation.
I have 50 yrs of experience reloading shotshells...and I wouldn't attempt it, even if I had a single stage press I just wanted to try it with...( if you don't resize the brass cups on the hull ...you're going to run into all kinds of feeding issues on pumps or semi-autos).
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Powder is not generic ....there are a dozen or more powders designed for shotgun use ...( and the mfg's use powders that are not generally available to us as reloaders). So you need a specific recipe, for a specific powder...Hodgdon Clays, Hodgdon International, Hodgdon Universal, Alliant Unique, etc... they're not even close to being the same....
Primers are not the same....Win 209's are different than Remington 209's, etc..
Wads are not all the same...there are some substitutions allowed from one brand to the other...but they are not universal...
not all presses resize the brass...( but you should do it -- if you want quality shells ).
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But shotshell reloading is easy ...you just need to do some reading, learn more about it...