First, find some cardboard, glue and markers. Cut out strips with cardboard for use, more than one centimeter wide.

Draw the shape of a gun on the cardboard. Cardboard is better. Add some cardboard to it. You should cut off a piece of cardboard to make it easier to put things.

Stick the air pump and spring firmly on the cardboard to prevent excessive recoil. Stick the adhesive tape vertically on two boards, add more glue, and be sure to be firm.

Gun (formerly known as spear, spear, musket and iron cannon) is a kind of weapon that uses the energy of gunpowder gas to fire bullets and attack unprotected or weakly protected living targets. Gun is the main weapon of infantry in the army and also the auxiliary weapon of other arms. Widely used in public security, hunting, sports competitions and other fields.

For a long time, "gun" has been the most basic fighting weapon in the hands of "soldiers". Along the track of their emergence, development and evolution, people can clearly see the tragic development history of human wars.

The ancestor of the gun is the firedoor gun. Rifles have changed: firebomb guns, matchlock guns, revolvers, flintstones, firing guns and gatling guns-renju guns, bolt rifles, machine guns, semi-automatic rifles and automatic rifles (assault rifles), which may eventually be replaced by ideal individual combat weapons in the future.