Introduction: The Lego C4 Semi-Automatic Crossbow

Picture of The Lego C4 Semi-Automatic Crossbow
The C4 Semi-Automatic Crossbow is the first semi-automatic crossbow which is as powerful as a regular lego crossbow. The crossbow can fire 35 feet or more, and has a 4 round capacity. I came up with the idea for a semi-automatic lego crossbow when I was trying to create a gun which could fire the Y1 Shotgun Shell powerful enough to separate it, which would be a crossbow, but also had a higher rate of fire (semi-automatic). The prototype which fired the Y1 eventually failed, but 5 months later, I readapted it to fire my standard crossbow round( (2x4)F ), which worked out very well. The gun works very well, and has a good rate of fire, and a good sight (similar to the M16 sight). It is powerful enough to go through paper, and ricochet very far. How the crossbow is semi-automatic but still looks like a crossbow is that the cover that goes over the magazine is wider than it would be on a normal semi-auto, which allows the rubberbands to still go on the trigger at an angle. This allows maximum power. The way the firing rubberbands work is that once one shot is fired, its corresponding rubberband flies to the front of the gun, and below the firing runway, where it stays. This prevents the used rubberbands from blocking the next shot.



For the C4.1 Semi-Automatic Crossbow (coming in a few weeks), these changes will be made: The top of the magazine holder will be altered to be more sturdy (The C4's hasn't broken yet, but its just a precaution), the firing capacity will be increased to 5 rounds, a stock will be added, and a bipod will be added.

Step 1: Main Forward Body

Picture of Main Forward Body

This step will build the base of the front half of the crossbow.

Step 2: Handle

Picture of Handle

This step completes the handle, which is the base for the back of the gun.

Step 3: Trigger Mechanism

Picture of Trigger Mechanism

This step builds the trigger mechanism and puts it on the handle piece.

Step 4: Building More of the Back

Picture of Building More of the Back

This step just builds more of the back pieces.

Step 5: Part of the Firing Mechanism

Picture of Part of the Firing Mechanism

This step builds some parts of the main mechanism..

Step 6: Filling in the Front

Picture of Filling in the Front

This step will finish filling the front of the crossbow with pieces, as well as make part of the area for the magazine to go in.

Step 7: The Rest of the Mechanism + Connecting the Parts

Picture of The Rest of the Mechanism + Connecting the Parts

This step will finish off the rest of the firing mechanism, as well as connect the front and back pieces of the crossbow.

Step 8: Rear Cover + Sight

Picture of Rear Cover + Sight

This step will build the cover on the mechanism and the rear sight with the tactical rails.

Step 9: Firing Runway

Picture of Firing Runway

This step will build the firing runway.

Step 10: Magazine Cover + Forward Sight

Picture of Magazine Cover + Forward Sight

This step builds the cover which will go over the area where the ammo comes out of the magazine, as well as the forward sight.

Step 11: The Magazine

Picture of The Magazine

This step builds builds the magazine.

Step 12: Front Handle

Picture of Front Handle

This step builds the handle in the front of the gun.

Step 13: Magazine Rod

Picture of Magazine Rod

This step builds the magazine rod.

Step 14: Ammo + Counterweight Rubberbands + Firing Rubberbands

Picture of Ammo + Counterweight Rubberbands + Firing Rubberbands

This step shows how to make the ammo, and where to put the counterweight and firing rubberbands.

Step 15: Loading

Picture of Loading

Before loading, you need to lubricate the insides of the magazine, all around each ammo piece, the firing runway, and the magazine rod (the brick part not the technic part) with a thin coating of Vaseline. Then, you can load in the order which the pictures show.


british_owl (author)2012-12-08

can you PLEASE make it where it does not take soooo manyy gearsss

An Villain (author)2009-11-03

when in dbout C4.

Say it with me everybody: Jamie want big boom.

soggymushrooms (author)2010-11-14

i can't 4 rbs. can you do a step on hw to load 4?

muttyfutty (author)2009-09-04

nice! I wonder how much space it takes on the Instructables server with all theese Images!!

Jesus. (author)2009-08-23


knexsuperbuilderfreak (author)2009-08-16

i gotta bulid this 5*

I'm going to be posting the C4.1 instructable soon so make sure you build that too :)

About This Instructable




More by Bitterberry9:The C4.1 Lego Semi-Automatic CrossbowThe Lego C4 Semi-Automatic CrossbowThe G1 Lego Under-Barrel Grenade Launcher
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