Dont know about Californian law but a good place to ask gun related questions is here.

call the cops…

I think it all revolves around magazine capacity. Ten rounds is rule of thumb there. So I am going to say they are legal so long as you stay away from hi cap mags.

m 16 / no m 4/ no 22 long /yes

Nancy (Polosi)
Barbara (Boxer)
Diane (Fienstein)
Care to answer @coolbeans question.

M16 and M4 are the real military weapons issued to the troops- full auto. I don’t think anyone can have THOSE at all. Even if someone was rich enough to buy one AND pass all the requirements to have a class 3 license they probably wouldn’t butcher one up converting it to .22 lr. The look alike knock offs that share most of the cosmetic features are probably more in line with what you are seeking-semi auto. I think even in CA people can own SKS’s and AK clones if the mags are 10 rds or less single stack, and the ammo for those is the real deal 7.62×39. So .22 cal should be ok. Or try google CA gun laws.

By M4 and 16 I assume you mean an AR clone because it would be a complete waste to gunsmith a perfectly good assault rifle into a vermin caliber. And like I said before I’m not an expert on Californian gun laws but if what @woodcutter is saying is true than it sounds like they still follow the federal assualt weapons ban which ended a few years ago.

AR
-15 yes/ sks ak47/yes you cant own military weapons .