Pretty much a Ruger MkII clone. I would try a Ruger mag and see if it works. I believe Ruger sued AMT over this gun and bankrupted the Cali company. OMC/AMT made some innovative guns like the .45 ACP stainless steel "Hardballer", the "Back up" pistols in both S/A and DAO and the Automag series. One of the issues that plagued many of their guns was "galling". The slides and frames of their stainless steel pistols were made from the same grade of steel and it caused some significant wear issues. Try Rig lube +P stainless steel lube. It is especially made for guns like this.