The text of the ordinance is here. (You have to scroll down.) "Assault weapons" are defined as (a) semiautomatic centerfire rifles that can accept a detachable magazine and have a pistol grip, thumbhole stock, folding or telescoping stock, or protruding forward grip, (b) semiautomatic centerfire pistols that can accept a magazine other than in the pistol grip, or have a secondary grip, and (c) semiautomatic shotguns that have any of the following: (1) A pistol grip or thumbhole stock; (2) Any feature capable of functioning as a protruding grip that can be held by the non-trigger hand; (3) A folding or telescoping stock; (4) A fixed magazine capacity in excess of 5 rounds; or (5) The capacity to accept a detachable magazine. Such guns lawfully possessed on June 15, 2018, can be grandfathered -- with a police certificate -- but cannot be transferred (within Boulder). Magazines with a capacity of more than 10 rounds are banned as of June 15. Persons lawfully in possession of such magazines on that date have until December 31 to get rid of them. There is an exception for pistol magazines (fitting within the grip) of up to 15 rounds. Bump stocks and "multi-burst trigger activators" are banned as well. This ordinance is worth studying because it shows some of the latest thinking of the antigun side.