1891 Argentine made in Germany won't fire

[vintage hunter]

Hmm, wondering if the OP's bolt is made up of mixed parts? Maybe a M'93/95 bolt shroud/firing pin assy screwed into an M '91 bolt body? If that's even possible...
OP, does your bolt shroud have the Argentine "shaking hands" inspectors stamp on the left side like in the second pic above? It should be on the cocking piece and firing pin too, IIRC.