5.56 x 45 Nato

The 5.56x45 NATO, or (5.56 NATO) is the ammo used by most of the modern weapons, This bullet was initially used in M16 Assault rifle,  it is a standard cartridge for NATO forces as well as many non-NATO countries.

Bullet Dimentions

      
If a bullet impacts with high enough velocity and yaws it can create dramatic wounding effects. This effect was first seen when US forces invaded Vietnam armed with M-16 AR in its early days while the US soldiers thought being armed with smaller bullet as compared to the enemy is a great disadvantage (Viet Cong were armed with Russian Ak-47 AR which uses 7.62 mm cartage).

 This bullet has almost half the kinetic energy compared to a 7.62 x 51 ammo how ever it has its own advantages, 
For example: 
>The 7.62 x 51 ammo has a heavy round and because of that it has excessive recoil, this is the reason soldiers and guns can't have high rate of fire in modern combat situations.
>Due to heavy ammo soldiers can't carry much of this ammo in combat and their clips can't carry more then 20 rounds while keeping their compact size, to big magazines can slow down reload speed and weight problems. 
If compared the M-14 magazines have 20 (7.62 x 51)rounds at 0.68 kg.
while a M-16 Magazines have 20 (5.56 x 45) rounds at 0.3 kg
This is half the weight of compared to 7.62 mm rounds which provides a massive advantage in warfare.


Performance:
  The 5.56x45mm NATO round with a standard 62 grams steel core bullets will penetrate approx  15 to 20 inch in soft tissue in standard conditions. 
  Because of its spitzer shaped bullet, it is prone to yaw inside a soft tissue, because of its impact velocity is roughly 761 m/s it may yaw around the cannelure of the bullet and then breaking into fragments.
 These fragments will then disperse into the flesh and internal organs causing additional damage to the body.

In simple words this is a DEADLY bullet.