I know its a game but watch how the first weapon is reloaded. Theres a strap connecting two opposite facing magazine and when you're done with one flip it around and connect the other. So would it work?
Sure it would work. Does work in fact. Soldiers have been using tape and clamps and all sorts of other arrangements for that very purpose about as long as detachable magazines have been commonplace on rifles. Look up "mag clamps"
Wouldn't work with a hi point, for obvious reasons. I mean unless you took two mags and epoxied the floorplates together or something.
butler creek 10/22 mags have lock tabs on them for just this purpose. ive done it with AK and AR mags but they can get heavy and dont fit into mag pouches if you empty them and need to relod fast. you end up dropping and posible loseing them in that case. i prefer a single mag with no add-ons.