Very interesting website for Husky serial numbers, calibers, etc. In the serial number lookup it lists the Mod 646 as "Model 640 in 6.5x55". One day maybe I'll be in the right pawn shop at the right time.

http://www.skydevaaben.com/index.xml

“When Tyranny becomes Law, Rebellion becomes Duty”

Colossians 3:17 (New King James Version)
"And whatever you do in word or deed, do all in the name of the Lord Jesus, giving thanks to God the Father through Him."