This is what the inside of a gun looks like when it's being fired

For all but the most familiar firearm users and operators, the inner workings of a gun remain a mystery. 

Everyone knows that firearms have a trigger, which when pulled fires a bullet. But between the pulling of the trigger and the bullet leaving the weapon, how does a gun function? 

The YouTube channel C&Rsenal has an ingenious way of explaining how various guns function - with the use of X-ray animations showing what happens as a user pulls the trigger. 

A selection of GIFs made from the channel's videos, showing some of the historical weapons used in World War I, are below.