The National Institute of Justice has a rating system for body armor (NIJ Standard 0101.03, 0101.04 and the interim 0101.05). As you add layers of a ballistic fiber, such as DuPont Kevlar®, you add protection. Bullet Proof Vests are tested not just for stopping penetration, but also for blunt trauma protection – the blow suffered by the body from the bullet's impact on the vest. Blunt trauma is measured by the dent suffered by a soft clay backstop to the vest – a maximum of 1.7" (44 mm) is allowed.
NOTE: The standard NIJ test rounds are listed below – tested vests stop many other comparable rounds, and lesser threats.
Level I (.22 LR; .380 ACP)
A Level 1 bulletproof vest provides protection against Lead Bullet Nose (LR LRN) bullets at velocity of 329 m/s (1080 ft/s ± 30 ft/s), 2.6 g (40 gram) .22 Long Rifle , and 6.2 g (95 gram) .380 ACP
Provides protection for Full Metal Jacketed Bullet Nose (FMJ RN) bullets at 322 m/s (1055 ft/s ± 30 ft/s). velocity.
Level IIA (9 mm; .40 S&W; .45 ACP)
This category bulletproof vest will protects against 8 g (124 gram) 9x19mm Parabellum Full Metal Jacketed Bullet Nose (FMJ RN) bullets at 373 m/s ± 9.1 m/s (1225 ft/s ± 30 ft/s) velocity; 11.7 g (180 gram) .40 S&W Full Metal Jacketed (FMJ) bullets at velocity 352 m/s ± 9.1 m/s (1155 ft/s ± 30 ft/s) and 14.9 g (230 gram) .45 ACP and Full Metal Jacketed (FMJ) bullets at velocity of 275 m/s ± 9.1 m/s (900 ft/s ± 30 ft/s).
A conditioned Level IIA bulletproof vest protects against 8 g (124 gram) 9 mm FMJ RN bullets fired at velocity of 355 m/s ± 9.1 m/s (1165 ft/s ± 30 ft/s); 11.7 g (180 gram) .40; FMJ bullets at a velocity of 325 m/s ± 9.1 m/s (1065 ft/s ± 30 ft/s) and 14.9 g (230 gram) and CP Full Metal Jacketed (FMJ) bullets at a velocity of 259 m/s ± 9.1 m/s (850 ft/s ± 30 ft/s).
The vest also protects against all threats described in [Type I].
Level II (9 mm; .357 Magnum)
This type of bulletproof vest protects against 8 g (124 gram) 9 mm FMJ RN bullets at a velocity of 398 m/s ± 9.1 m/s (1305 ft/s ± 30 ft/s) and 10.2 g (158 gram) .357 Magnum Jacketed Soft Point bullets at a velocity of 436 m/s ± 9.1 m/s (1430 ft/s ± 30 ft/s). Conditioned bulletproof vest protects against 8 g (124 gram) 9 mm FMJ RN bullets at a velocity of 379 m/s ±9.1 m/s (1245 ft/s ± 30 ft/s) and 10.2 g (158 gram) .357 Magnum Jacketed Soft Point bullets at a velocity of 408 m/s ±9.1 m/s (1340 ft/s ± 30 ft/s). It also provides protection against the threats mentioned in [Levels I and IIA].
Level IIIA (.357 SIG; .44 Magnum)
Level IIIA (.357 SIG ; .44 Magnum )
This bulletproof vest type provides protection protection against 8.1 g (125 gram) .357 SIG FMJ Flat Nose (FN) bullets at a velocity of 448 m/s ± 9.1 m/s (1470 ft/s ± 30 ft/s) and 15.6 g (240 gram) Semi Jacketed .44 Magnum Hollow Point (SJHP) bullets at a velocity of 436 m/s (1430 ft/s ± 30 ft/s). Conditioned bulletproof vest protects against 8.1 g (125 gram) .357 SIG FMJ Flat Nose (FN) bullets at a velocity of 430 m/s ± 9.1 m/s (1410 ft/s ± 30 ft/s) and 15.6 g (240 gram) .44 Magnum Semi Jacketed Hollow Point (SJHP) bullets with velocity 408 m/s ± 9.1 m/s (1340 ft/s ± 30 ft/s).
This type also protects against common handgun threats and threats mentioned in [Levels I, IIA, and II].
Level III (Rifles)
Conditioned type bulletproof vests protect against 9.6 g (148 gram) 7.62x51mm NATO M80 ball bullets fired at velocity 847 m/s ± 9.1 m/s (2780 ft/s ± 30 ft/s).
This type provides protection against the threats mentioned in [Levels I, IIA, II, and IIIA] as well.
Level IV(Bulletproof vest Piercing Rifle)
This type of conditioned bulletproof protection vest is affective against 10.8 g (166 gram) .30-06 Springfield M2 bulletproof vest-piercing (AP) bullets at a velocity of 878 m/s ± 9.1 m/s (2880 ft/s ± 30 ft/s). It also provides at least single hit protection against the threats mentioned in [Levels I, IIA, II, IIIA, and III].
