This is usually not a problem, but some modded weapons will use Action Pump for break-action weapons. The game doesn't check properly for when the player is allowed to switch weapons (unlike during reloads.) If you spam a hotkey immediately after firing, the game will let you swap weapons, and will backpack pump for you. If you're a second too late, the game will prevent you from animation cancelling. For long animations, this will result in time saved. In vanilla, this would likely just waste time due to input delay and equip animations.
This is usually not a problem, but some modded weapons will use Action Pump for break-action weapons. The game doesn't check properly for when the player is allowed to switch weapons (unlike during reloads.) If you spam a hotkey immediately after firing, the game will let you swap weapons, and will backpack pump for you. If you're a second too late, the game will prevent you from animation cancelling. For long animations, this will result in time saved. In vanilla, this would likely just waste time due to input delay and equip animations.