I tried to identify an old Belgian 22 (thread still on here) and found out that everyone in Belgium at the turn of the century that had a spare room manufactured firearms or parts for one company or another. Many makers were never registered and if they were the records have been lost over time. Have you taken the barred action out of the stock? There may be more markings on the underside. There are some Belgian makers marks websites if you can locate one on your rifle. Just courius, is it smooth bore or rifled?
Adam