Winchester 52-D barrel question

Dokey

I just bought what was supposed to be a heavy target barrel for my 1962 winchester model 52-D, but there are differences, although both are 28" long, my barrel measures 1.550" at the action and .870" at the muzzle, whereas the one just gotten is 1.00" at the action and .880" at the muzzle. Both barrels have the winchester info stamped on the left side with one exception, the proof mark on mine is on the left side in line with the graphics and the new barrel has the proof mark on top behind the rear screw tapping. Can anyone clarify what the difference is?

MIKE WISKEY

BOTH MY D'S ARE FAR BACK IN THE SAFE BUT I'LL GUESS THAT YOUR NEW BARREL IS FROM AN EARLIER RIFLE (B 0R C?).

Dokey

Correction on one of the measurements on my barrel at the chamber end, it's 1.055, not 1.550