About half of the state’s county sheriffs this week joined the battle against Colorado’s ban on gun magazines that hold more than 15 rounds, arguing that the law hinders peoples’ ability to defend themselves.

Although law enforcement are exempt from the ban, the sheriffs argued in their brief to the Colorado Supreme Court that civilians should have the same access to magazines as typical officers and deputies. If law enforcement agencies believe a magazine that holds 20 or 30 rounds is best for defense, then those magazines are the best option for regular people who want to defend themselves, the sheriffs argued.

“Citizens do and should copy sheriffs’ firearm and magazine selections so they will have reliable, sturdy arms for defense of self and others,” the brief stated. “These arms will be powerful enough for defense against violent criminals, and these arms will be appropriate for use in civil society, because sheriffs’ arms are not mass-killing military arms. Instead, sheriffs’ arms are best for defense of self and others, including against multiple attackers.”

Thirty county sheriffs, the Colorado Law Enforcement Firearms Instructors Association and the Independence Institute filed the brief on Monday in support of a group of gun rights advocates challenging the law’s constitutionality.

The state Supreme Court agreed in April to hear the case about the 2013 law, which banned possession of a magazine that holds more than 15 rounds, with exceptions for those who owned such magazines prior to July 2013. The law was passed in the wake of the Aurora theater shooting that killed 12 and injured 58 the year prior. The shooter at the theater used a large-capacity magazine to fire more than 60 bullets in less than a minute.

The Rocky Mountain Gun Owners and other gun rights advocates filed a lawsuit in 2016 alleging that the law was unconstitutional.

Both the Colorado Court of Appeals and a district court found the law to be constitutional. Similar cases in other states and in almost all federal courts have not been successful, Hannah Shearer, litigation director for the Giffords Law Center to Prevent Gun Violence, previously told The Denver Post.

Sheriffs from three Denver-area counties — Denver, Boulder and Arapahoe — were absent from the list.

The sheriffs and others in the brief argued that magazines that hold 20 or 30 rounds should be categorized as standard magazines because they are commonly included in the sale of firearms by default. Sheriff’s deputies often carry magazines of those sizes with them on patrol.

The brief offered an alternative to the ban. The state could instead require that a person have a state concealed handgun permit in order to own a magazine that holds more than 15 rounds, the sheriffs argued.

The Colorado Supreme Court has not set a date for arguments in the case.

The sheriffs who signed the brief, by county, are: