FWT barrel.
Some makers may have a "M70 Featherweight contour". I'm going to ask my 'smith this week. I recently had a Douglas barrel installed that was same contour for Winchester 70 magnum profile. The .30 cal. barrel (.300H+H)was same as original .338 contour. My (1955) .30-06 Featherweight "22 barrel measures about .550 at the muzzle.
Geoff