Curious that the single tube has the Sauer patent for an expensive method for joining tubes:

http://www.google.com/patents?id=pf1JAAA...p;q&f=false

May have begun as a 0.22 Winchester rimmed and then was altered/repaired to a diameter of 0.301" with the 172,28 plug gauge passing suggesting the 0.32" Winchester. The Sauer Tell was originally proofed for a 611 gauge(5mm) in the final state.

Kind Regards,

Raimey
rse