What you now have is an action from which you can make a dandy sporter. Do not worry about anything you might do to it....
Originally is was a Portuguese M.1937 Mauser Short Rifle
(1937 Contract) (Espingarda Mo. 937-A).
This is a 1937 contract rifle, sometimes referred to as "a first Portuguese contract". The rifle is similar to German 'Standard Modell' and K98k, except for the sling swivels, front sight and different markings. The receiver has a crest of Portugal and a date "1937". Made by Mauser-Werke A.G., Oberndorf a/N., as indicated by markings on the left side of the receiver. Nazi Eagle is stamped on the barrel, receiver, bolt, stock, barrel bands, trigger guard, magazine cover, buttplate and some other parts.
The A/N in the title means it was the Mauser Factory on the NECKAR River.
There is more than one Oberndorf in Germany, so they used the name of a nearby river to tell the difference.