You have to work up the load for your da's rifle. No two rifles will shoot the same ammo the same way.
Don't load 6.5 x 55, but I'd be thinking IMR4064, IMR or H 4895(close but not the same) or Varget with a 140 grain bullet. These are typical M1 Rifle powders.
As it's a semi-auto, you must FL resize every time, watch the case lengths(trim, chamfer and deburr as required) and OAL. Primary OAL thing is fitting in the mag.