If the development of the mag only involved dry runs, manually cycling rounds and not firing, I can see where someone interested in a 10 rounder might be willing to loan if they lived nearby. But I can't see where that would work. For the product to be dependable it would require some fairly extensive live fire. And of course the factory mags are rotary design. For the hi-cap I would assume a single or preferably double stack design would have to be developed for the rimmed .44, with substantial live fire at the various steps. Personally, without any financial interest involved, I wouldn't subject my Deerfield to that much wear. Bottom line, somebody has to buy some rifles. Possibly the manufacturer could buy them, keep up with the round count, then sell them with history after product development. In the long run however a firing platform would really need to be on hand for continuing QA and for returns. Good luck to you, I'd love to see a positive result; but it's hard to get most people to loan their guns out for a hunt, much less for industrial strength testing.
