Ranged Item / Ranged hostile Mob settings

Hi,

I've searched to no avail :(

I have a hostile, biped mob set as a creature spawn.

I have a custom gun item as a weapon and with texture and firing sound.

I have a item with texture for the bullet.

If the mob is set as ENTITY BASE: NONE then it can hold the gun, but doesn't swing an arm when attacking, the bullets are used but the sound doesn't play (it's attached to the gun).

If the mob is set as a Entity base: skeleton then  the bow overrides the gun, bullets are still fired but still no sound.

When the player uses the same gun, the sound works.