As most Officers will know, bulletproof vests are available in a variety of levels according to the protection it can offer you. This represents the vast range of ammunition an Officer my find her or himself threatened by. Bullet proof vests are certainly a necessity for Law Enforcement Officers (LEOs), as the FBI reported that in 2014 alone there were 165 assaults on LEOs every single day. Furthermore, 64 percent of all murdered Officers were killed by a handgun. Clearly, there is an incredibly pressing need for bulletproof vests, and for the right levels of protection. Understanding exactly what a vest can protect against will help ensure you are protected properly. The following list from SafeGuard Armor (www.SafeGuardArmor.com) compiles some of the most popular and available rounds, the firearms they can be used in, and what level of body armor you will need to protect against each.

9mm Parabellum

The 9mm Parabellum is commonly known as the most widely used handgun ammunition, thanks in part to its adoption by Law Enforcement. Made in Germany, the 9mm can be used in semi-automatic pistols as well, increasing its popularity. A Level IIa vest will stop this round at lower velocities, but at higher velocities a Level II vest is needed.

10mm Auto

The 10mm Auto suffers from high recoil, though is known for its stopping power. However, despite its use in certain branches of law enforcement it never gained the popularity of its shorter counterpart (the .40 S&W). The 10mm requires a Level IIa vest for protection.

.40 S&W

The .40 S&W was named for its creator, Smith & Wesson, and was designed as a shorter version of the 10mm Auto to be used by Law Enforcement. The .40 S&W has gained popularity among Officers since its introduction in 1990 thanks to its increased power and decreased recoil compared to similar rounds. Stopping the .40 S&W requires a Level IIa bulletproof vest.

.357 SIG

The .357 SIG was named for its manufacturer Sig Sauer, and is almost identical to the .357 Magnum. It does however boast decreased recoil and increased reliability, while also being compatible with autoloader platforms. Protection against the .357 SIG requires Level IIa body armor.

.45 ACP

The .45 ACP was designed to be used in John Browning’s prototype Colt Semi-automatic pistol, and gained popularity from 1911 thanks to its adoption by the US Army. The .45 ACP, also known as the .45 Auto, is famous for its use in the M1911 pistol, and is prized for its high velocity and moderate recoil. The .45 ACP is nevertheless heavy and costly to produce, and requires a bullet proof vest at Level IIa.

.357 Magnum

The .357 Magnum is credited with beginning the ‘Magnum era’ of handguns. This round was introduced in 1934 and can be fired from revolvers and certain semi-automatics like the Desert Eagle. It is renowned for its stopping power, and will need a Level II vest to protect against it.

.44 Magnum

The .44 Magnum is possibly the most famous ammunition in the world, thanks in no small part to Dirty Harry. However, until it was featured in the film it had been largely ignored and remained unknown from its introduction in 1955. This round has excellent stopping power, though this naturally causes high recoil and muzzle flash. For this ammo, a Level IIIa vest is needed.

Every level of body armor is decided upon by the National Institute of Justice and their rigorous testing methods. For more information on the ballistic protection of bullet proof vests, see the NIJ’s Official Documentation regarding testing and grading.