How does a bullpup assault rifle achieve a shorter overall length?

A bullpup assault rifle achieves a shorter overall length by positioning the rifle's action—specifically the bolt, receiver, and magazine—behind the handgrip and trigger.1

In this configuration, the barrel is bedded well back into the stock, allowing the end of the receiver to sit very close to the heel of the butt. Because the operating mechanism occupies the space typically reserved for the shoulder stock in orthodox designs, the weapon can maintain a standard barrel length while significantly reducing the total length of the firearm. By moving these components behind the trigger, bullpup designs like the Steyr AUG or the IWI Tavor SAR are able to be substantially more compact than traditional rifles, such as the M16, which feature the magazine and receiver ahead of the trigger.21