The first revision to the OA-93 was the
OA-96 in which a 30-round ammunition well is pinned and welded in place so that it cannot be detached. In addition, the OA-96 has a button in the rear which opens the upper receiver and can then be loaded manually. The second revision followed two years later.
OA-98 used a detachable magazine but the body was skeletonized to reduce the weight below the 50 ounce restriction to allow the OA-98 to have one more feature to be compliant with the 1994 Crime Bill. A piston driven carbine based on the pistol was made in 1993 and after the expiration of the
Federal Assault Weapons Ban from 2004 to 2007. ==References==