pygame not catching keyboard inputs

Question

I have a checkboard game set up with two gun sprites. I want to be able to move the gun sprites around freely but for some reason, pygame keeps missing my inputs. The code I have set up for the gun sprites is

while running:  
     for event in pygame.event.get():         
          if event.type == pygame.QUIT:             
               running = False      

     screen.blit(background, (0, 0))     
     
     if gunrotationcheck == 0: #Checks if gunrotationcheck is set to 0. If true, replace gun with up sprite
            gun = pygame.image.load('gun_up.png')
            screen.blit(gun, (gunx,guny))
     elif gunrotationcheck == 1: #Checks if gunrotationcheck is set to 1. If true, replace gun with left sprite
        gun = pygame.image.load('gun_left.png') 
        screen.blit(gun, (gunx-25,guny+30)) #Position fix
     elif gunrotationcheck == 3: #Checks if gunrotationcheck is set to 3. If true, replace gun with down sprite
        gun = pygame.image.load('gun_down.png') 
        screen.blit(gun, (gunx,guny))
     elif gunrotationcheck == 2: #Checks if gunrotationcheck is set to 2. If true, replace gun with right sprite
        gun = pygame.image.load('gun_right.png') 
        screen.blit(gun, (gunx-25,guny+30)) #Position fix

     events = pygame.event.get()
     for event in events:
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_a: #Move left
                gunx -= 50
            if event.key == pygame.K_d: #Move right
                gunx += 50
            if event.key == pygame.K_w: #Move up
                guny -= 50
            if event.key == pygame.K_s: #Move down
                guny += 50
            if event.key == pygame.K_j: #Turn left
                gunrotationcheck = 1
                gun = pygame.image.load('gun_left.png')
                screen.blit(gun, (gunx,guny))
            if event.key == pygame.K_l: #Turn right
                gunrotationcheck = 2
                gun = pygame.image.load('gun_right.png')
                screen.blit(gun, (gunx,guny))
            if event.key == pygame.K_i: #Turn up
                gunrotationcheck = 0
                gun = pygame.image.load('gun_up.png')
                screen.blit(gun, (gunx,guny))
            if event.key == pygame.K_k: #Turn down
                gunrotationcheck = 3
                gun = pygame.image.load('gun_down.png')
                screen.blit(gun, (gunx,guny))```

Answer 1

pygame.event.get() get all the messages and remove them from the queue. See the documentation:

This will get all the messages and remove them from the queue. [...]

If pygame.event.get() is called in multiple event loops, only one loop receives the events, but never all loops receive all events. As a result, some events appear to be missed.

Implement only one event loop:

while running:  
     for event in pygame.event.get():         
          if event.type == pygame.QUIT:             
               running = False  
          if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_a: #Move left
                gunx -= 50
            if event.key == pygame.K_d: #Move right
                gunx += 50
            if event.key == pygame.K_w: #Move up
                guny -= 50
            if event.key == pygame.K_s: #Move down
                guny += 50
            # [...]

     screen.blit(background, (0, 0))     
     
     # [...]

See also Faster version of 'pygame.event.get()'. Why are events being missed and why are the events delayed?