The M993 armor-piercing projectile can penetrate 7mm thick high-hardness armor steel plates at 500 meters, and is listed in the US Army's ammunition manual for use in M14, M60, M240, M24 sniper systems, etc.

In addition, the AK47 uses 7.62x39mm, M43 intermediate ammunition.

Finally, I would like to mention that bullets are divided into civilian and military types. Civilian bullets have a low charge, which results in low chamber pressure and low muzzle velocity. This is the kind of bullet that a thief can take away alive after being shot seven times.

Above... other special bullets rarely appear, so I won't introduce them.

Below is the body armor.

American NIJ 0101.06 standard:

Developed by the National Institute of Justice in the United States for the needs of law enforcement agencies for body armor, the latest 6th version of the standard was formulated in 2008 and will be replaced by the NIJ 0101.07 standard in 2021.

(Standards are just standards, the actual situation should be downgraded by half)

NIJ standard backrest recess depth shall not exceed 1.73inch/44mm.

Type I: Can stop .22 LR high-velocity lead bullets and .38 Special round-nose lead bullets.

Type IIA: Can block 9*19mm round-nose FMJ bullets and .40 S&W FMJ bullets.

Type II: Can block 9*19mm round-nose FMJ bullets and .357 Magnum bullets.

Type IIIA: Can stop .357SIG flat-nosed FMJ rounds and .44 Magnum SJHP rounds.

Type III: Able to block 7.62*51mm FMJ (US military code M80) bullets.

Type IV: Able to block .30-06M2 armor-piercing projectiles.

Huaxia GA 141-2010 standard:

Released on October 17, 2010.

The depth of the back recess shall not exceed 25mm.

Level 1: Able to block 7.62*17mm lead core pistol bullets.

Level 2: Able to block 7.62*25mm lead core pistol bullets.

Level 3: Able to block 7.62*25mm lead-core pistol bullets fired by 79mm with a long barrel.

Level 4: Able to block 7.62*25mm steel core pistol bullets fired by 79mm long barrel.

Level 5: Able to block 7.62*39mm Type 56 (AK47, also called M43 intermediate bullet) ordinary bullets.

Level 6: Able to block 7.62*54mm Type 53 ordinary bullets (note that it is 54MM, NATO's is 7.26X51mmNATO).

Stop saying that body armor is not bulletproof...
Chapter completed!