NPw .... Nitro Proof Weipert, Bohemia, Austria-Hungary,1891-1918; Vejprty, Czechoslovakia, 1918-1931 (?)
29....... 1929
These are common Austro-Hungarian markings which were also used post-WWI for a number of years in some of the countries that were constituted in 1918 when Austria-Hungary ceased to exist.
Weipert/Vejprty was an importand gun making center; probably the most well known maker was Gustav Fückert with his patented Kronengewehr (Crown Gun).
Regards,
Jani