After the WW1, the Gebrueder Rempt Gewehrfabrik in Suhl converted many Model 98 rifles into 2 shot repeating shotguns( these guns were produced in 12, 16 and 20 ga. and had the trade names Remo and Geha.)
In using the Mauser action to produce these shotguns, it was fitted with a shotgun barrel, locking shoulders and the diaphragm in the receiver ring were cut away sufficiently to permit passage of shotshells.
They used new walnut stock and converted military stock.
Many of these shotguns were imported in the U.S. during the early '20s by P. von Frantzius (later Sport, Incorporated), Chicago, Illinois, and the Pacific Arms corp.,San Francisco,California.
regards.