The rifle is a post WW1 produced sporter made at Danzig.
After WW1 ended, Danzig remained in operation for about a yr and 1/2. During that time they made both a 98 Mauser sporter and a .22cal bolt action rifle.
The 98 sporter was built on the same small ring 98 they had been making for the German army.
They took remaining actions and removed the Military markings (Danzig on the top of the front ring and K98 on the left wall of the action).
They replaced the left wall marking with the stamping you see on the OP's rifle .
The proof mark on the left sid eof the front ring is a Prussian proof mark used on commercial/civilian arms. The Serial number next to it was Danzig applied and those run into the about the 9000 range.
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The orig bbl would have been a 1/2 oct w/ half or full length rib.
The Allied Postwar Commision shut down the Danzig Arsenal and the others (Amburg, Spandau,,) . Danzigs arms making machinery was turned over to Poland IIRC.
The re-bbl w/ a full round bbl in 30-06 makes the rifle loose much of it's value as a 'Betw the Wars' German Sporting rifle built on a 98 Mauser.
If it had been still original with the orig bbl & sights,,and not D&T'd, a pad added,,nor the Lyman sight added (though those in themselves have some true value),,the rifle as original with a nice bore easily bring $800/$1000 in the right market.
Re-bbl'd as it is it's still a fine hunting rifle. The caliber is undoubtedly a good one and can do most anything needed in NA. The addition of the pad and the D&T and Lyman rear sight addition all drag the value down as a collector. But it's still a $500 rifle IMO.,,but I like early 98 sporters.