In researching this, I found from GOOGLE where the seller, bought it on AuctionArms. I then found where that seller bought it thru Simpson LTD. They listed it as a 8x51. They have sold many 8x54's and 57's, maybe a typo ???

As a 8x51mm it was intriging, as a 8x54mm a bit less so ??? Why is this ??? Turns out to be common ??? Too close to the 8x57's ??? I really like the stock profile, the action is fine, just feels nice, been awhile since I had a iron sighted rifle to practice with........

In looking this over, some observations. The stock is a fine fiddleback walnut cut down military stock. The rounded grip pistol grip is a obvious add on, cleaning rod hole filled, small filler pieces added in barrel channel where military rear sight was. I suspect that the original military 6.5 barrel was re-bored to 8mm, then the chamber cut. The existing brass would easily be made into 8x54 on production machinery.