You can buy and store outside the City of Denver, and they can sell it to you. The Statute prohibits owning and sale inside the city. No jurisdiction can make a law that effects people in other jurisdictions.
I believe if a Draco is a pistol by the definition below, you are ok. I would speak to an expert. How is it fired? from the shoulder or hip, with a rifled bore?
(5) Rifle shall mean a weapon designed or redesigned, made or remade and intended to be fired from the shoulder or hip and designed or redesigned or made or remade to use the energy of the explosive in a fixed cartridge to fire only a single projectile through a rifled bore for each single pull of the trigger and shall iSendnclude any such weapon which may be readily restored to fire a fixed cartridge.
a. All semiautomatic action, centerfire rifles with a detachable magazine with a capacity of twenty-one (21) or more rounds.
b. All semiautomatic shotguns with a folding stock or a magazine capacity of more than six (6) rounds or both.
Interesting note is that it exempts: (2) Any firearm that uses .22 caliber rimfire ammunition.