I have used and seen re-curve bows, .44 mag reveolvers, flint lock muzzle loaders, AR 15's, and glock 23's, etc.... Really the choice is yours, part of the fun of hunting there!
I would say a small caliber rifle there not very big should ask about the super boars and check out the European Trophy boar. Great place and well worth it.
Thanks! Your answer is awaiting moderation.