can not replace the weapon model of an npc

I know I’m doing wrong if someone can explain how I can replace the model of a npc weapon and tried to change the name of the weapon by default for example if the weapon is called ma5c and npc w_smg1 replaced the name of the ma5c to w_smg1 but the weapon is not seen in npc

[editline]12th October 2017[/editline]

Forget it and now they aregle it but now they do not shoot