The gun was proofed between 1910 & 1924. The barrels were 1.2755KG or 2.81 lbs. 70mm = 2 3/4" chambers and as Miller stated, it was nitro proofed. But that does not mean it should be used with today's heavy loads.

Can you show more of the gun? Sorta like describing an elephant after seeing it's toe....

Pete