Introduction: Ultimate M4 Barrel
This is almost exactly the same size as a real one and it can be used on a working gun. The red connectors prevent it from collapsing.
I've decided to make my own M4 to go with this barrel. You can still attach it to your own, just give me credit for it if you post it on a slideshow or instructable.
We have a be nice policy.
Please be positive and constructive.