I don't know how may attempts it took you to capture the rifling but it is a capital effort. I'd like to see the "Crown" over "V" to see if it is the German on-hand mark or possibly someone's trademark. I'm sure it is a cousin of the one on the following link:

http://www.doublegunshop.com/forums/ubbt...true#Post265003

Kind Regards,

Raimey
rse