AR-15

English Wikipedia has an article on:

AR-15 style rifle

Wikipedia

Initialism of ArmaLite Rifle, which was named after the company that originally designed the weapon.

AR-15 (plural AR-15s)

1. (trademark) A lightweight, semi-automatic rifle, based on the original design of the ArmaLite AR-15.
   • 2018 February 16, Julie Vitkovskaya, Patrick Martin, “4 basic questions about the AR-15”, in The Washington Post‎^[1]:

     An AR-15 once again made an appearance at a mass shooting, this time at a Parkland, Fla., high school on Wednesday. The suspect in the shooting, 19-year-old Nikolas Cruz, purchased the semiautomatic rifle about a year ago, according to a law enforcement official.

   • 2022 May 31, Susie Linfield, “Should We Be Forced to See Exactly What an AR-15 Does to a 10-Year-Old?”, in The New York Times‎^[2], →ISSN:

     Should We Be Forced to See Exactly What an AR-15 Does to a 10-Year-Old? [title]

   • 2023 March 27, Helen Lewis, “How Did America’s Weirdest, Most Freedom-Obsessed State Fall for an Authoritarian Governor?”, in The Atlantic‎^[3]:

     In the past decade, semiautomatic rifles like the AR-15 have become the weapon of choice for young killers, and I needed to see what America was willing to put into the hands of teenagers in the name of freedom.