The 93 has the traditional full heavy milled receiver barrel. The 95 and 96 have a newer hybrid barrel that in the military configuration has a lug below the gas block that accepts the under barrel grenade launchers. The newer barrel is thinner from the hand guard retainer forward. The newer barrel would have a sling mount on the hand guard retainer where the older design would have the sling mount at gas block. The 93 has a vented gas tube. The 95 and 96 have vented gas blocks instead. Bulgaria changed the design to make the rifle slightly lighter weight but mainly to allow stamped receiver AKM and AK-74 type under barrel grenade launchers to be mounted.
Despite some media reports, there were no AK-47s involved in the incident