Not sure if anyone has recommended this but you might give this a try. Q.M.W(Quick Modification Weapon) ESL file-44985-2021-6-3-1622715189. It only works with certain weapons but it's awesome in the long run as it allows you to scope, muzzle and rail attachments on the fly in game. I would also like to know what zombie mods you found so I might give them a try. Cheers!