this is a fantastic rifle, could be anything from 9,5x56 Mannlicher Schönauer to 375 H&H. I never heard of a 9,5 Peterlongo but he had some special cartridges so maybe. Could be also a 9,5x73 Miller& Greis or 9,5x66 Vom Hofe?
Peterlongo in Innsbruck allways had an offer for the africa hunter.