Spezialgewehrlaufstahl is literally " special gun barrel steel". Which is a pretty standard marking.

The other mark is the " pierced sole" ( as in a shoe) mark of the Suhl proofhouse.

You have an East German ( Deutsche Demokratische Republik - DDR ) gun.

Regards

GKT

Texas Declaration of Independence 1836 -The Indictment against the dictatorship, Para.16:"It has demanded us to deliver up our arms, which are essential to our defence, the rightful property of freemen, and formidable only to tyrannical governments."