Cartridge making is a complicated science. A manufacturer has to engineer reliability into the cartridge. Even the slightest degree of variance from cartridge to cartridge could produce disastrous results.

For example, a millimeter change in the overall length can change its velocity. In a semi automatic, the base of the cartridge is clamped firmly against the breech area where the firing pin protrudes when ready to fire. When the powder is ignited, the bullet jumps a gap from the case mouth, which holds the bullet firmly in the cartridge, to the rifling. A certain percentage of the burning gases will escape around the moving bullet until it creates a seal with the barrel. A millimeter variance in the distance the bullet has to travel before the bore is sealed could translate into a significant change in the velocity. Bullet manufacturers use exacting measurements to ensure their products do not have these variances.

Case length is only a single factor in this equation. Bullet manufacturers are asked to design bullets that will work in dozens of different guns, each with its own characteristic. It is expected that the same cartridge used in a 3-inch compact can also be used as a duty round for a duty weapon with a 5-inch barrel. Incidentally, this bullet needs to give the same performance in an Anchorage winter as it does in Death Valley in the summertime. Users would also be more than disappointed if the cartridge that was manufactured six months ago was not the same exact performer as one that came off the press yesterday.

Although it is known that a bullet will have a varied performance in different layers of clothing, through different materials and in different situations, no one has ever approached a bullet maker for a product specifically for "cold urban environments" or "tropical areas with few vehicles." It is simply assumed the cartridge manufacturers are up to the impossible task.

Furthermore, cartridges are expected to fire a projectile that expands when told to expand, or for a bullet to hold together through a variety of media. Law enforcement users want cartridges to be accurate, as heavy as possible and yet generate little recoil, resulting in comfortable shooting sessions.

If that wasn't enough, the cartridges cannot generate too much flash when shot at night. This is simpler than it seems. When pistol powder is ignited, it does not explode. Rather, it burns at a consistent rate, causing a rapid and even acceleration of the bullet down the barrel. Ideally, the volume of powder in the cartridge completes its burn just prior to that point where a bullet escapes the muzzle. If a cartridge gives ideal performance in a handgun with a 5-inch barrel, a 2-inch barrel might look like a flame thrower. This is why the engineers that work for ammunition-manufacturing companies are not just the "stubby pencil" type. They are practical and knowledgeable technicians who constantly test and retest their products under real conditions.

Benefits of testing
The committee or officer responsible for duty ammunition selection bears an enormous responsibility. They must decide on something that someone may call upon when lives are in a balance. Agencies should review their duty ammunition at regular intervals, at least every couple of years. This will insure new products are considered and old ammunition is used in training.

The purpose of this article is to provide agencies with only one piece of the puzzle when it comes to predicting a bullet's performance, not the solution. Agencies should never base their choices on a single data source or test.

Although there are many factors that aid ballistic scientists in predicting performance, few will be as reliable or reassuring as firing into ballistic media. This conclusion is based on several assumptions. It would be impossible and morally repugnant to test a bullet in living, breathing flesh. On the other hand, there is no reliable way to translate the piercing of gelatin into actual trauma or, especially, the ability to stop the flight. There will never be enough actual shooting data for a single cartridge to be certain of the outcome in every given situation.

Ballistic testing uncovers trends that suggest how a bullet cartridge combination will work. If a bullet can consistently expand in gelatin, it most likely will expand in flesh. If the path of the bullet includes a threat-stopping organ, the rapidly expanding, higher velocity, heavier bullet will improve or facilitate the stop.

Accuracy testing also identifies trends. It is known in competitive shooting circles that firearms favor certain cartridges. Although an inaccurate cartridge is easily identified, a single session or series of sessions can only be anecdotal when looking at accuracy data. An agency can only make an intelligent accuracy statement when every firearm is accuracy tested with the same cartridge.

What our testing team expected to find in our accuracy testing was confirmation the manufacturers do their homework. Additionally, consistency measured by small standard deviation suggests production consistency and reliability.

Testing methodology
There are eight testing events: bare gelatin, heavy clothing, steel, wallboard, plywood, automobile glass, heavy clothing at 20 yards and automobile glass at 20 yards. Because the testing team needed to survey a large number of cartridges and add other information to the testing, the team used two tests that would produce the largest amount of usable data: bare gelatin and glass barrier. The bare gelatin test simulates an unobstructed bullet into tissue. The glass barrier test simulates a bullet through a windshield.

The testing team used unmodified handguns typically found on duty. A test like this means several hours of preparation to fire only a dozen bullets a day. This kind of test is labor intensive and requires a range with a lot of flexibility and minimal interruption. The testing was conducted with the assistance of the Livingston (California) Police Department, and officers willing to donate their time and labor in order to advance the science.

The bullets were fired through standard production duty weapons. One should immediately recognize this is also an independent variable. Cartridges perform differently in different weapons. The testing team did not find any bullets whose accuracy potential would disqualify them. This means that using the duty weapons, the testers were able to easily pass a 25-yard static firearms qualification course with any product tested. This should not come as any surprise. No bullet manufacturer would put a product on the market whose accuracy was questionable. It would be recognized immediately.

The other tests added were a comparison between the accuracy of frangible rounds and their duty round equivalent, chronographed velocity and accuracy with a duty weapon. Even with the abbreviated testing protocol, the test team was committed to shooting thousands of rounds in a variety of ways.

Bullet performance
The generally accepted method of testing bullet performance is to fire into ballistic gelatin. Ballistic gelatin is a 10-percent mixture of gelatin similar to, but firmer than, the food product. The gelatin is molded into blocks and fired at under particular conditions. The purpose of using gelatin is to simulate living tissue as close as possible. The conditions for testing using gelatin are used by the FBI and are generally acceptable in the ballistics community.

The Law Enforcement Technology test team used Vyse Ballistic/Ordinance Gelatin. This allowed the testing team to see completely through the blocks while compiling data. Ballistic gelatin has to be mixed a day ahead of time and poured into molds. In order for the test to be valid, each block must be refrigerated and calibrated just before use. A block that does not meet calibration cannot be used.

The accepted standard of performance in bare gelatin is a 12-inch penetration. The logic behind this is simple. From any angle, a wound channel will create traumatic injury if it penetrates 12 inches or beyond. If a bullet performs satisfactorily, it must be able to do so regardless of what gets in front of it. This includes a windshield, a limb or any combination of independent variables. If two bullets are tested side-by-side and they achieve the same amount of penetration, the bullet that makes the biggest hole is considered to be better.

There are many schools of thought about these factors. For example, a projectile with an extreme velocity will create a temporary channel in the media, which can be measured. Some might argue that a temporary hydrostatic shock, which contributes to the temporary channel, is a performance factor. Other schools of ballistic thought conclude that only the permanent wound channel should be considered.

Although 12 inches was nominal penetration in testing circles, we found it was a little tougher for a 9mm bullet to achieve this standard after intersecting the glass barrier. In the .40 S&W; and .45 category, 12 inches was commonplace. Heavier bullets will carry the most amount of energy to the target, all other things considered equal. Achieving the right combination of velocity, penetration and expansion has initiated a trend of moderate weight, which means faster bullets. This is most evident in the 140 to 170 grain .40 S&W; lightning bolts.

Shooting bullets into bare gelatin sets the standard of the tests to follow. If a bullet failed to perform in bare gelatin, it was easy to predict the results for the rest of the test. For example, every bullet that failed to retain its original weight when fired through bare gelatin experienced the same performance after a glass barrier. However, bullets that successfully held together and penetrated 12 inches or more in bare gelatin did not necessarily do well after the glass barrier.

Bullet consistency
There are many ways to measure the consistency of bullet manufacture, but the most reliable means is to chronograph the velocity of a large sample. After that, measuring how much it deviates from the average of the sample will give the tester an idea the consistency.

The test team used an Oehler 35P Chronograph, which automatically prints calculated data while firing. The standard deviation from the chronograph readings often will explain why one cartridge is more accurate than another. For example, one of the most accurate groups at 25 meters was 1.88 inches. This cartridge was Zero's No. 921. This cartridge also had a rather low standard deviation.

Expanding cartridge performance
Cartridge performance is an elusive concept because it cannot be clearly defined. While it may be academically satisfying for a bullet to be able to pierce 17 inches of ballistic gelatin after a barrier, what good is it? It is actually most desirable for a cartridge combination to deliver all of its energy within the tissue of the target intended without overpenetration.

Most experts agree that rapid expansion during penetration is desirable. Ideally, bullets will increase its frontal mass to about 150 percent or so during expansion. Most bullets have pre-scored areas to encourage the jacket to peel back in a controlled manner. The antithesis of this concept is a jacket that separates from the lead core.

If rapid expansion is ideal, would a jacketed bullet be considered superior if the jacket completely peels back and separates? Although, creating a separate wound channel by a bifurcated projectile might be effective, it makes performance unpredictable.

Cartridge manufacturers have several strategies to increase the performance of a bullet after it strikes the target. The study of this performance is a separate science called terminal ballistics.

The most common manufacture of projectiles is a lead core with a brass or copper jacket. Some companies taper the jacket near the nose to increase its expansion, in addition to the hollowpoint. Most modern law enforcement hollowpoints are pre-scored. This means that they have little cuts in them to encourage a "flowerlike" or "mushroom" expansion as they strike the target.

The law enforcement trend is toward "bonded" bullets. These are cartridges that have bullets where the copper jacket is bonded to the lead core either by heat, pressure or proprietary process. Bonding a bullet prevents the jacket from separating from the core, especially after striking a barrier before the target.

Another means of connecting the bullet with the core is to partition it, where the copper core has a bottom chamber of lead separate from the top. Remington uses brass jackets, which is harder than copper. They bonded these jackets to the core. There was no question in the testing team's mind this strategy worked.

The bottom line is that a bullet needs to enter targets with sufficient velocity to penetrate the "vital zone" and then stop abruptly. This abrupt stop means that the energy of the bullet is dumped into the target, creating a shock. Thus, a higher velocity bullet will have more energy to deliver, all other things equal. The rate of expansion and amount of expansion now comes into play. The quicker a bullet gets bigger, the more efficiently it will dump its energy. The larger it gets in the course of its mission, the better. A bullet with a large cavity in the front and scored areas that encourage expansion will generally perform better than another without these features.

However, the density and hardness of the material comes into play here. When the bullet is traveling quickly through the media and expanding quickly, the idea is to prevent overexpansion.

Unfortunately, the media itself is the independent variable. The science of terminal ballistics has many related concepts. When a bullet strikes bare gelatin, it decelerates through a consistent material. The predictors for performance in this material are simply to have an expanded bullet when it finally comes to rest. It has to penetrate an ideal distance without leaving any material behind. It is impossible to predict what a law enforcement bullet will be fired into. Not every target is as consistent in makeup as ballistic gelatin.

Test findings
The conclusion of testing found Remington, Winchester, Zero and quantity to be up to the task. The testing revealed standout performances such as Winchester's 9mm RA9BA, while other races were to close to call. One of the comparisons too close to call was the superior performance of the Winchester RA40BA and the Remington GSB40SWB.

Winchester provided cartridges and the 9mm and .40 caliber category that were similar in all other aspects except the inside of the bullet. The 9mm RA9124TP recorded the same velocity as the 124 grain RA9BA and expanded quicker in bare gelatin. In the after barrier test the RA9BA excelled. In fact, this 9mm looked like a .40 S&W; when it came to rest.

The Remington 124-grain 9mm was similar in performance. It expanded faster in the after barrier test but penetrated more than an inch less in the after barrier test. This invites another age-old bullet debate: is a larger frontal area after barrier more desirable than a deep penetration? In any case, both bullets were excellent offerings for duty rounds.

Applying the results
The best use of bullet testing data is to recognize established trends in a bullet's performance. It would be safe to say a bullet exhibited satisfactory results in the after barrier test if it could repeat this performance in a similar gun of a different brand. Bullets that demonstrate consistent accuracy in several tests will be more likely to deliver reasonably good accuracy in a different gun. Agencies should take this information and use it to narrow their product selection.

Ultimately, the best conclusion from this information is the fact that no bullet testing protocol will ever be complete. The other deduction one can make is the fact that no bullet cartridge combination is perfect for every application. For example, one off our top performers in bare gelatin was Zero brand No. 862, a 165 grain .40 S&W.; It penetrated a full 17 1/4 inches and expanded to an unmatched .861 diameter. It was reasonably accurate and exhibited high velocity. In some of the accuracy tests, it was superior to most of the other .40 S&W; offerings. However, it was only a moderate performer in the after barrier tests. The jacket separated from the core, though only after it achieved 12 inches of penetration. Our testers thought that this was excellent performance for a non-bonded bullet.

Frangible bullets
Frangible bullets are cartridges that look and function like their duty counterparts but designed to impact steel targets and disintegrate. The bullets exhibit all of the characteristics, including reliable feeding and functioning, of their duty round counterparts.

Frangible bullets are generally lead free and use non-toxic primers. They are designed for close quarter steel plate shooting. Made of powdered metal, they are ricochet resistance and exhibit reduced splash back when shooting steel plate targets. For law enforcement, frangible bullets are ideal. Entry teams can practice realistic scenarios at near contact distances without the risk of shrapnel blowback.

It is important that users realize frangible bullets are real bullets and just as hazardous as their duty counterparts. Yet, the bullets are not designed for use on anything but practice targets.

The frangible bullets tested where from Remington and Winchester. The bullets were fired into steel plates at several different angles and the amount of the deflected material was measured by placing paper collectors at different distances. As suspected, the amount of splash back closer than about 15 feet was still hazardous. However, both Winchester and Remington products performed as advertised past these distances with a hard target reducing them to powder.

The Winchester and Remington frangible products struck their targets in the same exact patterns as their duty round counterparts. Strangely enough, the point of impact was only similar with the same brand of bullet. This means when fired through the same gun, the same brand impacted in the same area on the target at 25 yards. For example, the Winchester RA9124TP duty rounds struck the target in the same area as the RA9SF but not the same area as the Remington bullets. The difference was fairly insignificant, but notable. The test team was able to repeat this test consistently.

Taking the results of the tests into account, it is recommended if the agency has adopted Winchester bullets for duty, use Winchester bullets for frangible practice. If the agency has adopted Remington Bullets, use Remington Disintegrator bullets for practice.

Simply an entry point
A bullet manufacturer's most powerful ally is its reputation. Logically, if Hornady, Zero, Winchester or Remington were known for poor performance they would not last in the law enforcement business. The test team encourages law enforcement agencies to conduct their own tests with the duty weapons they issue. Ballistic gelatin is readily available and little has to be done to modify a firing range for this type of testing.

In fact, it would be irresponsible for an agency to make their cartridge selection based on a single data source or a single test. The testing team suggests agencies use this article as a starting point for their testing.