Instructor Dennis Tueller

Dennis Tueller

by

At a Glance

Salt Lake City police sergeant behind the Tueller Drill and the 21-foot rule.

Schools

  • Salt Lake City Police Department (firearms instructor)
  • Glock (armorer instructor)

Accomplishments

  • Published “How Close Is Too Close?” in SWAT magazine (1983)
  • Originated the Tueller Drill reactionary gap
  • Produced a police training video of the same name

Salt Lake City Police Department

  • March 1983 SWAT magazine article “How Close Is Too Close?”
  • Tueller Drill is a self-defense training exercise 
  • 21 Foot Rule – an attacker with a knife could cover 21 feet  before you can draw
  • Armed Citizens’ Legal Defense Network, Inc.

Instructor Dennis Tueller

Dennis Tueller

https://armedcitizensnetwork.org/the-tueller-drill-revisited

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  • Glock Armorer Instructor
See Dennis Tueller and more than 50 other trainers in the After Action.net Firearm Instructors directory.

About Dennis Tueller

Dennis Tueller is a former Salt Lake City Police Department sergeant and firearms instructor whose work gave the training world the Tueller Drill and the widely cited “21-foot rule.” While running time trials with volunteers, Tueller found that a person armed with a knife could cover 21 feet and strike in about 1.5 seconds, roughly the time it takes a trained officer to draw and fire. He chose 21 feet because officers already trained to shoot from that distance. He published the results in the March 1983 issue of SWAT magazine under the title “How Close Is Too Close?” and released a police training video with the same name.

The drill changed how police officers and armed citizens think about distance, awareness and the time needed to respond to an edged-weapon threat. Some departments wrote it into policy, and it has been tested and debated ever since, including on MythBusters in 2012 and in a 2021 peer-reviewed study in Police Practice and Research. Trainers today generally treat it as a lesson in reaction time rather than a fixed legal line. Tueller has also served as a Glock armorer instructor and is associated with the Armed Citizens’ Legal Defense Network.

Key Facts

  • March 1983: Published “How Close Is Too Close?” in SWAT magazine
  • 2012: MythBusters tested the drill in its “Duel Dilemmas” episode
  • 2021: Rule examined in a peer-reviewed study in Police Practice and Research

Learn More

Sources

Across the Gun Websites Network

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