Am currently deployed in Iraq on a PSD task and have been issued with the Zastava M21S in 5.56mm. Can anyone advise me on a picatinny rail mount that can replace the front handguard? We need to source a compatible mount ASAP as the rear iron sights on this weapon are a flip-up type and cannot be locked in the upright position. They constantly get knocked back down, getting into and out of vehicles and rubbing against LBV during weapon changeover drills. In short, a reliable optical system needs to be mounted on a 1913std rail.