I recently bought a full chronos, but havnt got the achivement for it. Must I take it all out the set for this or put it all in my activated inventory?

it takes a while just wait

You have to have it in you inventory for 24 hours.

You dont need all chronos items you need an chronos PACK

Actually, you need all chronos items. I've got full magnetite and full gladiator with all items and not packs. :v
I'm not sure if you would get full color achievements with packs.

Let packs be packs they dont give you full set achievements unless you unlock em(if the pack is totally full not just force and lax pack).
It takes a while for it to update.

Ok thanks guys it was just an issue of time today I got the achievements