Maybe Karbin m/94-96 (Engineer's carbine)
You may have the m/94-96 version used by the Army Fortification Service and Army Engineers. This can be identified by a) no bayonet lug b) sling swivel on the butt is underneath, not at the side. They were converted from the normal carbine and are very rare - rarer than the standard model. The stock disc hole was also simply filled with with a brass plate, so it hasn't lost an original disc of the kind you know from the m/96 rifles - it never had one.
To be sure, we need good photos.
280 would be a steal for the normal carbine. For the Engineer's carbine - words fail me!
:wave: