N = Nitro
BLG = Bleigeschoss = lead bullet
SCH H = Schuetzenhuelse = standard target shooting case
8.15x46R Norm repeats this. Probably added later in America, a German would have marked 8,15x46R.
NORM = normalized, case shape and dimensions as standardized in 1909.
Take the rifle apart and post all the markings under the barrel.These may show the proofhouse and proof date, maybe barrel dimensions and rifling twist too.
Meister 1937 = owner won an unidentified, local?, championship in 1937.