Here are some attachment ideas so that you can make your own! Here are four I made. Enjoy!
Step 1: Scope
Here is a scope I made for the gun and is actually pretty accurate. Pretty cool right?
Step 2: Simple Sight
Here is a simple sight I made. Similar to the scope but is way smaller.
Step 3: Detachable Carry Handle
Here is a carry handle I created that detaches, like the other stuff. Allows you to carry the gun easily.
Step 4: Mini K'nade Launcher ([KNEX Grenade] Launcher)
Here is my favorite. The k'nade launcher. K'nade is a play on words of K'NEX and grenade. It connects on to the gun so you can make a K'nade (KNEX grenade) by taking two blue connectors and connecting them, and putting a white rod on it. The feed the white rod into the barrel and then it can shoot the K'nade. (Note: Using more that 1 rubber band on the K'nade Launcher ram rod will give better range. If you put a lot of bands put a rubber band in front of the orange connector on the ram rod so it makes it so that the connector doesn't fly off the ram rod.)