Brett,

Winchester used Nickel Steel alloy barrels from the start of production in August 1912 through early 1932 when they switched to the Proof Steel (chrome-moly) alloy barrels. From a shooter’s perspective, the Proof Steel alloy barrels are better due to the higher tensile strength. From a collector’s perspective, the Nickel Steel barrels are slightly more desirable due to the fact that they are older (earlier production).

Bert