What will ... er... does.. it use for magazines?
Note that Kurt chose his cartridge dimensions for good reasons, that pesky front rib tends to get in the way. If you stretch that x39 case too long, you run into two problems: 1) the cases will start hitting the rib, causing challenges with feeding, stacking, etc. 2) most .308 bullet are intended for the .308 Win or .30-06. Both allow a generous amount of bullet out in front of the case. Try to use those bullets in the restrictions of the AR magazine and there is a good chance that you will seat them too deep. This then means you end up limited in your bullet selection (note the very long discussion on the .25-223 versus .25x40, as well as the .25-45 Sharps regarding bullet seating).
Ballistically it sounds like the 7.62x45 from the Czechs (old VZ round), which really does not have much over the 7.62x39. For a novelty, sure, buy it. For "big game", buy either a big rifle (.308 platform) or one of the larger rounds that has proven capable of taking large game (there are 3 main calibers out currently, with more in the works apparently)