The so-called “21-Foot Rule” is a widely referenced but often misunderstood principle in law enforcement and self-defense training. Originally developed to provide clarity in high-stakes situations, it has sparked debates and misconceptions over the years.
In this article, we’ll explore insights from experts on this topic including Maxx Budiac of the USCCA, criminal defense attorney Tom Grieve, Dennis Tueller (the rule’s originator), Utah legal expert Ken Wallentine, and self-defense trainer Icy Mike. These unique perspectives reveal the complexity and evolving understanding of this principle.
Origins of the 21-Foot Rule

In 1983, Dennis Tueller, a Utah police trainer, published a pivotal article titled “How Close is Too Close?” in SWAT magazine. As Tueller explained in an interview with Ken Wallentine, the “21-Foot Principle” emerged from experiments designed to determine how quickly an attacker with a knife could close the distance on a defender.
Tueller found that an assailant could sprint 21 feet in approximately 1.5 seconds – the same amount of time it typically took a trained officer to draw and fire two shots from an open carry holster. This discovery highlighted a crucial concept: the reactionary gap, or the time lag between perceiving a threat and responding effectively.
Not a Rule, but a Guideline

Both Tueller and Wallentine emphasize that the “21-Foot Rule” was never intended to be a rigid standard. Tueller himself refers to the term as a “bastardized misappropriation” of his findings. The principle was meant to encourage situational awareness, preparedness, and an understanding of human reaction times – not to dictate a specific distance for engaging a threat. Wallentine supports this view, pointing out that variables like terrain, lighting, obstacles, and the attacker’s speed all influence the reactionary gap.
The Reactionary Gap in Action

Maxx Budiac, training manager for the USCCA, explains that the reactionary gap – the foundation of the 21-Foot Principle – is vital for concealed carriers. Unlike police officers using open-carry holsters in Tueller’s original experiments, concealed carriers face additional delays in drawing their weapon.
Budiac stresses that practicing realistic scenarios, including drawing from under clothing or jackets, can help carriers improve their response time. However, he cautions against relying solely on the 21-foot benchmark, noting that every situation is unique.
Misinterpretations in Law and Training

Criminal defense attorney Tom Grieve sheds light on how the 21-Foot Rule has been misapplied in legal contexts. In the case of Buchanan v. City of San Jose (2019), the Ninth Circuit Court addressed whether officers acted appropriately in using deadly force against a knife-wielding suspect at a distance greater than 21 feet.
Grieve explains that the case almost led to the rule being codified as law, which would have dangerously simplified self-defense standards. Instead, Grieve emphasizes the importance of considering the totality of circumstances rather than adhering to a fixed rule.
Real-World Complexities

Icy Mike, a self-defense trainer and YouTuber, brings a practical perspective to the discussion. Demonstrating the Tueller Drill with role-playing scenarios, he highlights the many factors that can influence an encounter. For example, a shooter’s accuracy under stress, the attacker’s unpredictability, and environmental obstacles all play critical roles. Mike argues that focusing solely on distance oversimplifies the complexity of real-world confrontations. His advice: train extensively and adapt to the situation at hand.
Action Beats Reaction

Wallentine underscores a fundamental principle: action beats reaction. This means that an attacker who initiates an assault inherently has the advantage, as the defender must first recognize the threat, decide on a response, and then act. This sequence creates a delay that can be fatal if the defender is unprepared. Tueller and Wallentine both advocate for proactive movement, such as sidestepping or seeking cover, to break the attacker’s momentum and regain control of the encounter.
Training for Realistic Scenarios

Maxx Budiac offers practical advice for concealed carriers looking to refine their reaction times. He recommends setting up controlled drills at home using replica weapons, a stopwatch, and a training partner. These exercises simulate the timing of real-life scenarios, helping carriers identify gaps in their response. Importantly, Budiac reminds carriers to stay within the boundaries of the law, as unnecessary displays of firearms can result in criminal charges.
The Problem with Tunnel Vision

Both Wallentine and Tueller discuss the psychological challenges that arise in high-stress situations, including tunnel vision and inattentional blindness. These phenomena can severely impair a defender’s ability to process their surroundings and react effectively. Training to break tunnel vision – such as scanning the environment after engaging a target – can improve situational awareness and decision-making under pressure.
Dispelling Myths About the Rule

Icy Mike addresses one of the biggest misconceptions about the 21-Foot Rule: the belief that it grants automatic justification to shoot a threat within that range. He emphasizes that the rule is not a license to use deadly force but a guideline to highlight the potential speed of an attack. Factors such as the attacker’s behavior, available cover, and alternative options (e.g., de-escalation or retreat) must all be considered before deciding to engage.
Expanding Beyond 21 Feet

Wallentine and Grieve both note that the 21-foot distance is not an absolute threshold. In some cases, a threat at 30 feet – or even farther – may still warrant a defensive response. For instance, an attacker armed with a firearm or exhibiting erratic behavior may pose a clear and imminent danger, regardless of the exact distance. This reinforces the need to evaluate each situation based on its unique circumstances.
Training and Awareness

The value of the 21-Foot Principle lies in its ability to raise awareness about the limitations of human reaction times. However, it’s essential to remember that no single rule can account for the complexities of real-world encounters. Situational awareness, ongoing training, and a clear understanding of the law are critical for making informed decisions in high-pressure moments.
A Principle, Not a Rule

The “21-Foot Rule” is not a rule at all – it’s a principle rooted in human performance and the realities of self-defense. As Tueller, Wallentine, Grieve, Budiac, and Icy Mike have shown, its true value lies in fostering preparedness and adaptability. By understanding the reactionary gap and training for realistic scenarios, individuals can improve their chances of responding effectively when microseconds matter.

Growing up in the Pacific Northwest, John developed a love for the great outdoors early on. With years of experience as a wilderness guide, he’s navigated rugged terrains and unpredictable weather patterns. John is also an avid hunter and fisherman who believes in sustainable living. His focus on practical survival skills, from building shelters to purifying water, reflects his passion for preparedness. When he’s not out in the wild, you can find him sharing his knowledge through writing, hoping to inspire others to embrace self-reliance.