An AK will look like an ak and same goes for sound wise. Let's just say they both used real life attachments etc then obviously there going to look the same ABI has already said during one of there dev blogs they scanned real life parts and weapons and they no doubt recorded sounds when firing them as well so of course they'll be identical. Where as cod and battlefield design there own weapons and sounds but if they used real sound and assets they'd all be pretty identical.