The G.43 should take any German GI or standard 7.9 round. (I am not sure about the Turkish stuff, some of which is reportedly very hot.)
But, at the price those things are today, it is probably not a real good idea to shoot one. They have had problems, one of which was the first type dust cover which often fails to engage properly and gets bent or broken.
There is also the standard warning that they can be fired without the bolt locking lugs, but I have always felt that was unlikely.