So I am making this guide to show the effectiveness of heavy armor and of AP ammo. The shots were fired into the upper back at point blank range. If you have any questions or want anything else tested just tell me in the comments.This guide only shows guns used on competetive, there are too many to do everything else. ~EDIT~ Due to popular request HP ammo has been added for the guns that can use it (not bolt-action snipers).

M9 (600 RPM):
No armor: 1
Light armor: 3
Heavy armor: 10
AP Ammo
Light armor: 1
Heavy armor: 4
HP Ammo
Light armor: 3
Heavy armor: 13

M1911 (600 RPM):
No armor: 1
Light armor: 2
Heavy armor: 8
AP Ammo
Light armor: 1
Heavy armor: 4
HP Ammo
Light armor: 3
Heavy armor: 10

Makarov (700 RPM):
No armor: 1
Light armor: 3
Heavy armor: 10 (reload needed)
AP Ammo
Light armor: 1
Heavy armor: 4
HP Ammo
Light armor: 3
Heavy armor: 13

M45A1 (600 RPM):
No armor: 1
Light armor: 2
Heavy armor: 8
AP Ammo
Light armor: 1
Heavy armor: 4
HP Ammo
Light armor: 3
Heavy armor: 10

Model 10:
No armor:
Light armor: 1
Heavy armor: 8 (reload needed)
AP Ammo
Light armor: 1
Heavy armor: 3
HP Ammo
Light armor: 5
Heavy armor: 12

UMP-45 (600 RPM):
No armor: 1
Light armor: 2
Heavy armor: 8
AP Ammo
Light armor: 1
Heavy armor: 4
HP Ammo
Light armor: 3
Heavy armor: 10

MP5K (900 RPM):
No armor: 1
Light armor: 3
Heavy armor: 10
AP Ammo
Light armor: 1
Heavy armor: 4
HP Ammo
Light armor: 4
Heavy armor: 13

MP40 (550 RPM):
No armor: 1
Light armor: 3
Heavy armor: 10
AP Ammo
Light armor: 1
Heavy armor: 4
HP Ammo
Light armor: 4
Heavy armor: 13

AKS-74U (700 RPM):
No armor: 1
Light armor: 2
Heavy armor: 5
AP Ammo
Light armor: 1
Heavy armor: 2
HP Ammo
Light armor: 2
Heavy armor: 6

M16A4 (780 RPM):
No armor: 1
Light armor: 1
Heavy armor: 4
AP Ammo
Light armor: 1
Heavy armor: 1
HP Ammo
Light armor: 2
Heavy armor: 4

M4A1 (740 RPM):
No armor: 1
Light armor: 1
Heavy armor: 4
AP Ammo
Light armor: 1
Heavy armor: 1
HP Ammo
Light armor: 2
Heavy armor: 4

ERB (710 RPM):
No armor: 1
Light armor: 1
Heavy armor: 3
AP Ammo
Light armor: 1
Heavy armor: 1
HP Ammo
Light armor: 1
Heavy armor: 3

AK-74 (600 RPM):
No armor: 1
Light armor: 2
Heavy armor: 5
AP Ammo
Light armor: 1
Heavy armor: 2
HP Ammo
Light armor: 2
Heavy armor: 5

AKM (600 RPM):
No armor: 1
Light armor: 1
Heavy armor: 4
AP Ammo
Light armor: 1
Heavy armor: 1
HP Ammo
Light armor: 2
Heavy armor: 5

FAL (620 RPM):
No armor: 1
Light armor: 1
Heavy armor: 3
AP Ammo
Light armor: 1
Heavy armor: 1
HP Ammo
Light armor: 1
Heavy armor: 3

Mosin (40 RPM):
No armor: 1
Light armor: 1
Heavy armor: 3
AP Ammo
Light armor: 1
Heavy armor: 1

SKS (600 RPM):
No armor: 1
Light armor: 1
Heavy armor: 4
AP Ammo
Light armor: 1
Heavy armor: 1
HP Ammo
Light armor: 2
Heavy armor: 5

M40A1 (40 RPM):
No armor: 1
Light armor: 1
Heavy armor: 3
AP Ammo
Light armor: 1
Heavy armor: 1

L1A1 (620 RPM):
No armor: 1
Light armor: 1
Heavy armor: 3
AP Ammo
Light armor: 1
Heavy armor: 1
HP Ammo
Light armor: 1
Heavy armor: 3

So all in all my thoughts are light armor is a waste of money and just slows you down and AP ammo is necessary if facing someone with heavy armor. Also, HP ammo is great if you are hitting legs and arms, not chest. Special thanks to Bot Taco and The Russian Bear for being my targets and test dummies, be sure to give them a thanks. Also, look out for my next test which is the effectiveness of buckshot vs slugs at range. IF YOU SEE WHAT YOU THINK TO BE A MISTAKE PLEASE POLITELY LET ME KNOW IN THE COMMENTS