I know this isn?t the better information you were asking about but I?m just going to toss out my two cents.
If you absolutely, positively feel you must arm yourself while in Denver but fear of having your shit confiscated or your vehicle impounded is a genuine concern for you then why not simply choose a firearm that is more socially acceptable in Denver and just be done with it?
In other words, rather than trying to interpret their bullshit laws and then jump through hoops doing silly things like modifying magazines or whatever, why not just take a decent handgun or if you insist on a long gun perhaps a nice lever action rifle or maybe a pump action shotgun?