DENVER (KDVR) — Several municipalities in Boulder County passed new gun restrictions on “assault weapons,” but what does that mean?

In a package of new gun restrictions passed on Tuesday night, Boulder City Council wrote that assault weapons have “unique features that allow shooters to rapidly fire a large number of rounds — more than is ever needed for lawful self-defense — while maintaining control of the firearm in order to accurately target and kill more victims.”

The King Soopers shooter, for example, used an AR-style pistol said to be designed for close combat, “because of the short length and ability to fire rifle rounds that can penetrate ballistic-resistant vests,” according to the council.

In Aurora, the theater shooter used an assault rifle and a 100-round drum magazine.

In the package of ordinances, the council defined assault weapons and explained some of their features. Here is a breakdown of what’s in the bills.

Assault weapon features

Boulder City Council identified some of the features used in assault weapons and explained how they work:

  • Detachable magazine: Firearms that can accept detachable magazines allow a shooter to attach magazines of any size available for the firearm and quickly reload the weapon with prefilled magazines. In some cases, magazines can hold as many as 100 rounds
  • Pistol grip: To counteract the movement that occurs during rapid fire, assault weapons are typically equipped with features that allow the shooter to steady the weapon. A pistol grip, not typically found on a sporting rifle or shotgun (which would be fired from the shoulder), allows the shooter to control the firearm more accurately—and lethally—by maneuvering the weapon or shooting from the hip during rapid fire;
  • Thumbhole stock: As with a pistol grip, a thumbhole stock allows the shooter to control the firearm during rapid fire;
  • Folding or telescoping stock: A folding or telescoping stock folds or collapses to make the weapon easier to conceal and transport;
  • Flash Suppressor: A flash suppressor enables a shooter to mask their location by reducing the visible signature of the firearm when it fires; and
  • Barrel shroud: As with a pistol grip and thumbhole stock, a barrel shroud allows the shooter to steady the firearm during rapid fire. The shroud encircles the barrel of the firearm and allows the shooter to hold it without getting burned.

What is an assault weapon?

For the purposes of the new laws, the council specifically defined an “assault weapon” as the following:

  • All semi-automatic center-fire rifles that have the capacity to accept a detachable magazine and that have any of the following characteristics:
    • A pistol grip or thumbhole stock;
    • A folding or telescoping stock;
    • A flash suppressor; or
    • A shroud attached to the barrel, or that partially or completely encircles the barrel, allowing the bearer to hold the firearms with the non-trigger hand without being burned, but excluding a slide that encloses the barrel.
  • All semi-automatic center-fire pistols that have any of the following characteristics:
    • A threaded barrel;
    • A secondary protruding grip or other device to allow the weapon to be stabilized with the non-trigger hand;
    • A shroud attached to the barrel, or that partially or completely encircles the barrel, allowing the bearer to hold the firearm with the non-trigger hand without being burned, but excluding a slide that encloses the barrel;
    • A flash suppressor;
    • The capacity to accept a detachable ammunition feeding device at some location outside of the pistol grip;
    • A manufactured weight of 50 ounces or more when unloaded;
    • A buffer tube, arm brace, or other part that protrudes horizontally under the pistol grip;
    • A fixed magazine that has the capacity to accept more than 10 rounds.
  • All semi-automatic shotguns that have any of the following characteristics:
    • A pistol grip or thumbhole stock;
    • A folding or telescoping stock;
    • A fixed magazine capacity in excess of five rounds; or
    • The capacity to accept a detachable magazine.
  • Any firearm which has been modified to be operable as an assault weapon as defined herein.
  • Any part or combination of parts designed or intended to convert a firearm into an assault weapon, including any combination of parts from which an assault weapon may be readily assembled if those parts are in the possession or under the control of the same person.”

The city defines “semi-automatic” as “a firearm that fires a single round for each pull of the trigger and automatically chambers a new round immediately after a round is fired.”

What is a large-capacity magazine?

Boulder defines a “large-capacity magazine” as “any ammunition feeding device with the capacity to accept more than 10 rounds,” but not including any of the following:

  • A feeding device that has been permanently altered so that it cannot accommodate more than 10 rounds.
  • A 22-caliber tube rim-fire ammunition feeding device.
  • A tubular magazine that is contained in a lever-action firearm.”

What is a rapid-fire trigger activator?

One example of a rapid-fire trigger activator is a bump stock, which replaces a rifle’s standard stock and is already banned under the federal law that also prohibits fully automatic machine guns among civilians. In the ordinance, these rapid-fire trigger activators are specifically defined as:

  • A device that attaches to a firearm to allow the firearm to discharge two or more shots in a burst when the device is activated; or
  • A manual or power-driven trigger-activating device that, when attached to a firearm, increases the rate of fire of that firearm.

Other illegal weapons in Boulder

Boulder also bans other weapons within the city, including blackjacks, gas guns, metallic knuckles, gravity knives and switchblade knives.