Kansas Magazine and Assault-Weapon Rules: What the Law Actually Says

The controlling statute is K.S.A. 12-16,124, titled "Firearms and ammunition; regulation by city or county, limitations." It's a preemption law, meaning it strips cities and counties of the power to regulate firearms in most ways, magazine capacity and weapon type included.

The Kansas Office of the Revisor of Statutes publishes the operative language in subsection (a):

"No city or county shall adopt or enforce any ordinance, resolution or regulation, and no agent of any city or county shall take any administrative action, governing the requirement of fees, licenses or permits for, the commerce in or the sale, purchase, transfer, ownership, storage, carrying, transporting or taxation of firearms or ammunition, or any component or combination thereof."

Read that list again: commerce, sale, purchase, transfer, ownership, storage, carrying, transporting. A local ban on 30-round magazines or AR-pattern rifles would hit several of those categories at once, which is exactly why it's off the table.

Subsection (b) goes a step further and makes the preemption retroactive: any local ordinance that conflicted with this rule and was adopted before July 1, 2015, is "null and void." Cities don't get to keep an older ordinance on the books just because it predates the current language. The statute itself has been amended several times since it was first enacted in 2005, most recently in 2015, but the trend across every revision has been the same direction: tighter preemption, not looser.

There's also no federal backstop filling this gap. The federal Assault Weapons Ban, which banned certain semi-automatic rifles and capped new magazines at 10 rounds, expired in September 2004 under its own sunset clause and was never renewed by Congress. So the question of whether Kansas "has" these restrictions isn't close. Neither the state nor the federal government currently regulates magazine capacity or defines assault weapons by statute.

Separately, if you go looking through the Kansas criminal code for a definition of "assault weapon" or a magazine round-count limit, you won't find one. Chapter 21, Article 63 of the Kansas Statutes Annotated covers weapons crimes (criminal use of weapons under K.S.A. 21-6301, criminal carrying under K.S.A. 21-6302), and neither section references magazine capacity or cosmetic rifle features like pistol grips, folding stocks, or threaded barrels. Kansas simply never wrote that category of law.

Picture a guy at a gun show in Wichita buying a stack of 30-round PMAGs for his AR-15. Nothing stops that purchase. There's no state form, no capacity cutoff, no waiting period tied to magazine size. The transaction is governed by the same federal background check rules (if it's through an FFL) that apply to any other firearm accessory sale.

Now picture a family moving to Lawrence from a state like Colorado or Illinois that caps magazines at 15 or 10 rounds. Their pre-existing 30-round magazines, legal or not back home, become perfectly legal the moment they're in Kansas. There's no "assault weapon" registry to update, no grandfathering paperwork, no permit renewal tied to the move.

Suppose a city council in a place like Overland Park, sitting in the more urban Kansas City metro area, wanted to pass its own ordinance restricting magazine capacity or banning semi-automatic rifles by feature list, something a handful of cities in other states have tried. Under K.S.A. 12-16,124(a), that ordinance would be void the moment it's enacted. The city would have no enforcement authority, and if it tried anyway, a lawsuit citing the preemption statute would end it fast.

Consider a trooper running a traffic stop on I-70 outside Topeka and spotting a loaded 30-round magazine sitting on the passenger seat. It doesn't matter if the driver has Missouri plates, Colorado plates, or Kansas plates. Kansas doesn't care about the magazine's capacity, and the stop doesn't turn into a weapons charge just because the magazine holds more than 10 or 15 rounds.

Finally, consider someone building an AR pistol or buying a rifle with a threaded barrel, flash hider, and adjustable stock at a shop in Topeka. In a feature-test state, that combination of parts might legally reclassify the gun as a prohibited "assault weapon." In Kansas, none of those features change anything. The gun is bought, sold, and possessed the same way a hunting rifle is.

The preemption statute does carve out a short list of things cities and counties can still do, but none of them touch magazine capacity or firearm type. K.S.A. 12-16,124(c) lists four narrow carve-outs:

None of these let a city set a round-count ceiling on magazines or define certain rifles as "assault weapons" for purposes of sale or possession. The carve-outs are administrative and tax-related, not substantive gun-control authority, and the Kansas Attorney General's office has repeatedly read the preemption statute broadly in formal opinions addressing other local ordinances that tried to regulate carrying and sales.

There's no penalty section to point to here, because there's no underlying prohibition. You can't be charged with illegal possession of a "large-capacity magazine" or an "assault weapon" in Kansas, because the state never created those categories of crime. No registration, no permit, no paperwork of any kind attaches to buying or owning a standard-capacity magazine or a semi-automatic rifle with whatever features you want on it.

That said, don't confuse this with other, unrelated firearm offenses that do carry penalties in Kansas, like felon-in-possession charges or criminal use of weapons under K.S.A. 21-6301. Those statutes exist and carry real consequences, but they're tied to who's holding the gun or how it's used, not to magazine size or rifle cosmetics. A city that tried to enforce its own magazine or assault-weapon ordinance anyway would be the one facing legal exposure, not the gun owner, since the ordinance itself would be void under state law.

A lot of confusion on this topic comes from people applying rules they heard about from other states, or from an expired federal law, onto Kansas.

Key Point: Kansas's approach here isn't an oversight. The legislature deliberately chose to preempt the field so gun owners face one set of rules statewide instead of a patchwork between, say, Wichita and a neighboring county.

• K.S.A. 12-16,124, Kansas Office of the Revisor of Statutes

Last Reviewed: November 07, 2026