Simple K'nex Pistol Upgrade

My simple pistol, but it shoots farther (I think) and you can use BB's too. It also features an extended barrel and a bipod.

Step 1: Handle

Build the handle:

Step 2: Barrel

Build the barrel:

Pic. 1: Completed barrel
Pic. 2: Parts in middle layer
Pic. 3: Close-up of front
Pic. 4: Top-front
Pic. 5: Close-up of bottom

Step 3: Trigger and Firing Pin

Same as before

Step 4: Extension and Bipod

Build both:

Pic. 1-3: Bipod attachment
Pic. 4: Bipod legs
Pic. 5: Extension
Pic. 6: Front view of extension

Step 5: Assembly

Put the gun together: