Sometimes you make alternative shells that are very close to shells you made in the past, like an APHE and APFR(AP frag) rounds, they are similar enough that a duplication feature would allow you to create it with a few clicks rather than start from scratch.
#Duplication feature in the shell designer
hard mason
hallow mantle
It would also be useful to be able to duplicate shells from the customizer blocks
humble island
This is probably a duplicate feature request, but i don't mind seeing it again as an APS user
Being able to quickly load, edit, and save shells missile-style would be amazing in my opinion
I also have somewhat standardized shell designs for different types of guns, so I've had to do a lot of copying the exact same shells over and over and this sort of feature would cut down on that a lot
mental wren
this seems like a incredible time saver