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The Use of Less Lethal Weapons in Corrections, Part 5 – Impact Weapons


At the high end of less lethal force options are weapons whose primary function is to deliver kinetic energy. The problem with these weapons and munitions is that there are almost too many to choose from.

You have your choice of .68 caliber, 12 gauge, 37mm or 40mm platforms. Some have rifled barrels. Some are smooth bore. These weapons can fire baton rounds (made of foam, plastic, rubber, Styrofoam or wood), drag-stabilized, fin-stabilized, pads (rectangular or round), pellets (large or small), or encapsulated rounds that can be filled with everything from chemical agents to marking dyes. And most of these rounds can be fired with either black powder or smokeless powder.

It would be easy to get swallowed up in this subject. The easiest way to approach it is to look at what your needs are and how impact weapons will fit into your overall tactical strategy.

There are really only two types of problems in corrections where impact weapons are likely to come into play: disturbances and cell extractions. You could add hostage situations, but they are rare and a unique animal that call for the introduction of deadly force and SWAT tactics which are beyond the scope of this series. That said if impact weapons are to be used in disturbances and cell extractions, then what is their role and how do they fit in with the other tools we have already discussed?

The Los Angeles Sheriff’s Department jail disturbance statistics over the past decade show that impact weapons are the least likely tool that will be employed. They are used less than ten percent of the time. Verbal commands and chemical agents along with a show of force end most disturbances.

Should this prove insufficient a volley of noise/flash distraction devices followed by the limited introduction of a response team is usually enough to bring the situation to a satisfactory end. In less than one in ten incidents are inmates still standing after a team makes entry and refuse to surrender. These inmates are the ones volunteering to be shot with impact weapons. These are usually the shot-callers. So I like to think of impact weapons as shot-caller removal tools.

The question now is what weapon do you want to fire that is the most reliable and can deliver the most accurate round. Also, what is the effective range of that round? Some 37mm rounds claim to be accurate up to 100 meters. This is great if, A: the inmate stands still and waits for the round to reach him, B: nobody else steps in the way and takes the hit before the round gets there and C: your personnel train regularly with these weapons and practice taking these long shots, often from elevated platforms such as guard towers, under stress. For these reasons shots beyond 50 meters are highly problematic. This is still a long distance and is well beyond what will be required in almost all indoor problems.

Ken Hubbs’s and David Klinger’s study for the National Institute of Justice on the use and effects of impact munitions found that 88% of field encounters occur at less than 40 feet and 70% occur at less than 30 feet. This report was also significant for it showed that in 60% of incidents the firing of a second round was required to achieve incapacitation. No comparable study of impact weapons in a correctional setting has been done, but it is likely that the average distances for use in corrections are similar. Uses in cell extractions are more numerous than those in jail disturbances and no doubt negate the longer shots taken in yard disturbances. This, of course, is the shortcoming of drawing conclusions from averages. You know best the situations you are likely to encounter and should select your weapons and ammo based on the scenarios you most probably will encounter.

Using impact weapons in cell extractions presents a different set of problems. The maximum effective range is not the primary concern. The minimum safe distance the round can be fired is the issue? Also, is a shot available in the target area recommended by the manufacturer for that given round? Most manufacturers are now recommending that center mass shots be avoided and ordnance be fired waist or below, or at the extremities. The use of impact weapons in cell extractions is also complicated by the fact that most inmates are aware of our tactics and barricade their cells and don their own makeshift protective gear. Almost all less lethal rounds will be defeated by a jail mattress.

There is a temptation to want to shoot the mattress out of an inmate’s hands, but this should be avoided. If an inmate plays peek-a-boo with his mattress at the wrong moment, the chance of shooting him in the face arises. The best way to create a shot in the cell when an inmate is holding a mattress is to introduce a Noise Flash Diversionary Device and then take the shot in the window of opportunity that is created when the inmate is disoriented and lowers his protective barrier. The introduction of chemical agents or Pepperball rounds may create this effect, as well, but an NFDD is more likely to yield positive results.

A Few Things That Are Good to Know

Kinetic Energy
As stated above, the primary function of impact weapons is to deliver kinetic energy. It is important to understand what kinetic energy is to help do your assessment on which platform and round or rounds will work best for you. The nice thing about kinetic energy is that it can be reduced to an easy to understand math formula. KE = (1/2)(M/G)V². M is the weight of the projectile. G is its acceleration due to gravity, i.e., 32.2 ft/sec. And V is the velocity of the projectile in feet per second squared. The heavier the object and the faster it is traveling the more kinetic energy it has.

Blunt Trauma, Penetrating Trauma and Fluid Shock
When an impact projectile strikes the body the goal is transfer enough kinetic energy through blunt trauma to incapacitate an inmate without causing penetrating trauma that may kill him. Remember, incapacitation means causing a tactical break in an inmate’s behavior. This does not mean turning him completely compliant. The blunt trauma caused by these rounds will cause some injury. Though, if fired correctly and from the correct distances, they should not cause penetrating trauma that will make them lethal.

A round does not need to penetrate the body to kill, however. The energy that is transferred from the projectile into the body is known as fluid shock. In July 2007 Mike Coolbaugh, the batting coach for the minor league Tulsa Drillers, was struck and killed by a line drive while standing in the first base coach’s box. As a result, all major league coaches are now mandated to wear batting helmets while coaching the bases.

A small or frail individual is far more likely to sustain significant injury due to fluid shock. That is one reason why aim points are so critical and is also why most manufacturers are recommending the waist and below and the extremities as targets for munitions instead of center mass when firing munitions delivering significant amounts of kinetic energy. Fluid shock on high energy rounds fired center mass can and have stopped hearts. When they strike an inmate in the head they can have the same result that they did on baseball field in

Penn Arms PGL65-40 (40mm)


One fatality resulted in Boston from an FN303 round that was fired indiscriminately into a crowd of rowdy Red Sox fans celebrating the team’s historic comeback from a three game deficit against the hated Yankees in the 2004 league championship series. The round penetrated the eye of sixteen year old girl Victoria Snelgrove, an innocent bystander in the crowd, and killed her. Some early less lethal shotgun rounds that were not drag stabilized also caused penetrating trauma.

Some of these rounds are still out there and should be avoided. When fired properly, from the right distance, with due consideration to aim point, the majority of less lethal impact munitions will be effective and not lethal.

Trajectory Degradation

Penn Arms SL-6 (37mm)

Based on the kinetic energy formula above it is clear that the amount of energy delivered to a target varies based on the distance a shooter is from an inmate. This is known as trajectory degradation. Another concern impact munitions is that some of it can be lethal at or near the muzzle. It is critical to follow the recommendations for minimum firing distances given by the manufacturers. The area where a particular piece of ordnance is no longer lethal to where it is no longer effective is called the “sweet spot.” Each munition has a different “sweet spot” and the “sweet spot” of similar rounds can vary from manufacturer to manufacturer.

In 2000 the Los Angeles Sheriff’s Department, in a joint venture with Penn State University’s Institute for Nonlethal Defense Technologies, conducted testing on 79 different impact munitions. The results of that study showed that drag-stabilized munitions have the greatest amount of trajectory degradation and fin-stabilized and rectangular pads were next.

Direct Fire vs. Skip Fire
Some ordnance can only be direct fired. Some can only be employed safely when skip fired. Some can be used both ways. Does this matter? Skip firing is required for wooden baton munitions. It is recommended for foam and rubber batons and it maximizes the effect of multiple pellet munitions. The LASD/Penn State study showed that by skip firing multiple pellet rounds the beaten zone is halved and saturation is doubled and as much or more energy is generated as direct firing. Rounds kept a tighter pattern and hit harder. When skip firing at close range there is a risk that ricochets can hit the response team. Wooden baton rounds fired indiscriminately can cause serious injury. It would be prudent to avoid them.

Munition accuracy varies widely from round to round. Again the LASD/Penn State study revealed that 56% of the rounds tested could not reliably hit a man-sized target at 25 yards. The most accurate rounds tested at near range were drag-stabilized. The most accurate at far range were bladder bullets and sponge rounds. This testing was conducted prior to the availability of the FN303. So the munitions fired from this very accurate weapons platform were not tested.

TAC700 Pepperball Gun, above, and FN Herstal FN303

37mm vs. 40mm
The oldest impact weapons in our armories are the 37s. These come with a single shot five or six round magazine. Some have smooth bore barrels others are rifled. If your agency has not committed to either platform, go with the 40s. All the research and development dollars are being spent on 40mm platforms because that is what the Department of Defense wants for the military.

The 40mm platforms are also more versatile and allow you to fire just about everything through them. You will need at least two different 37mm platforms to accomplish a mission that can be accomplished by one 40mm. What you lose with the 40mm is that the size of the magazine will not permit you to fire eight inch projectiles and the maximum range of projectiles is about 40 yards. But as was noted above, it is highly unlikely that you are going to hit a moving target while under stress at distance with a round that travels at only about 325 feet per second.

Pepperball Guns vs. the FN303
Both of these weapons used compressed air to launch their munitions, but their similarities almost end at this point. The maximum effective range of a Pepperball round against a target is 60 feet while the FN303 is effective out to 50 meters. A Pepperball round strikes with 10 to 12 foot pounds of energy. The FN303 round packs a 16 to 24 foot pound wallop.

A Pepperball gun does have a 250 round hopper contrasted with the 15 round magazine in the FN303, so more rounds are available, but the FN303 is the most accurate of all impact weapons. Its munitions are fin-stabilized. Pepperball rounds are subject to the elements. The FN303 can also be outfitted with an EO Tech holographic site to even increase its accuracy.

For area treatment of chemicals the Pepperball gun is the clear winner, but if it is your intention to deliver kinetic energy on a target the FN303 is the superior weapon. The new generation TAC 700 Pepperball gun provides the option of three preset modes: single, three burst and full automatic.

I would caution against the full auto setting, but the three burst mode is very effective. There are pros and cons to both weapons platforms as a kinetic energy platform. The deal breaker for the FN303 for many agencies may be its cost and the bum rap it got because of Victoria Snelgrove’s death in Boston.

Less Lethal Shotguns
The safe minimum distance for less lethal shotgun munitions is too great for use in cell extractions or close quarters engagements. This is also the platform that has killed more than any other, although that had as much to do with the type of round originally used as the platform itself. Still, due to the long minimum range for the munitions its use in a custodial setting is limited. With this in mind it would be best to keep these weapons outside and on the street and deploy one or more of the less lethal platforms described above inside jails and prisons.

Black Powder vs. Smokeless Munitions
Munitions employing black powder have a louder report, produce a bigger kick and generate an impressive tongue of flame. They are not as accurate as smokeless rounds and cause far more fouling of the barrel requiring more cleaning. The big bang a black powder round generates is impressive, but the accuracy of the smokeless rounds makes more sense.

The World in Which We Live
In a perfect world we would have all the response team personnel we want armed with whatever weapons we deem they need and constantly train them to respond to all our tactical problems. We all know this will never happen. In the world in which we do live we need to keep things as cost effective and easy to train as possible.

Simplicity is one of General JFC Fuller’s nine principles of war. Impact weapon platforms and munition options are numerous. Unless you can afford to keep and train a response team to almost SWAT levels, do not overwhelm yourself and your personnel with too many weapons and different types of munitions. One training adage states, “You can train to a higher level than you can maintain.” Keep this in mind when selecting your impact weapon platforms and munitions.

If you can only afford to purchase and train on one platform, I would recommend the six shot 40mm. An EO Tech holographic site is also available for this weapon, though the bead site it comes with is very good. The 40mm offers almost all the different munition options you should need. The 40mm eXact impact sponge round hits with 80 to 108 foot pounds of energy and is effective out to 120 feet. This round is a great option. For times when you might need to engage multiple targets at once, or it might be necessary to skip rounds around a barricade, multiple pellet rounds or foam rounds are also available to accomplish this mission. I would load only one type of munition in a weapon at one time, however. This will require you to have at least two weapons available, but this is still your most cost effective option.

If you can afford to purchase and train on additional platforms, consider the FN303 for longer shots. The Tac 700 version of the Pepperball gun is also another good support weapon because it gives you the ability to saturate an area with OC in addition to giving you secondary kinetic support, but its uses as an impact weapon outdoors and at distances is limited.

Remember, in keeping with the overarching philosophy for less lethal weapons use, impact weapons are only part of a larger tactical plan and their effects need to be reversible over time. The use of impact weapons may temporarily take down a shot-caller or clear an area of inmates, but some other tactic must ensue to end your problem and shot placement is critical to ensure that use of these weapons does not result in serious injury. Take a good hard look at all the weapons and munitions out there before deciding what works best for you.

Lieutenant John J. Stanley, M.A., is a twenty-seven year veteran of the Los Angeles Sheriff’s Department. He has worked a variety of assignments including, custody, patrol, training and administrative support. He is considered an expert on less lethal weapons and tactics. He provided corrections scenarios for the Institute for Non-Lethal Defense Technologies Applied Research Laboratory at Penn State University and contributed to its on-line Less Lethal Weapons class. John spent over a decade at LASD’s Custody Training Unit teaching classes such as Tactical Communications, Jail Intelligence Gathering, Tactical Weapons, Squad Tactics and Cell Extractions. John also was the lead instructor for LASD’s Custody Incident Command School (CICS) a class designed for sergeants and lieutenants and the Executive Incident Command School (EICS) for captains and above. He is a member of the California Tactical Officers Association and has published almost forty articles on law enforcement tactics and legal history.