One day I went airsofting with my AK-74U(Because my MK.18 Mod 1was too big). And on my way home I thought, since there is no M4 CQBR, why don't I make one by myself. So I went to market, bought myself a Colt M4 and start making it.
Anyway here is what u need for making M4 CQBR
1-Airsoft Colt M4
Step 1: Measure the Length of Barrel.
Before u get into sawing and gluing measure the length of the barrel. Since there is inner barrel I measured it with pencil.
Step 2: Mark It! 1
If u r done with that mark the place where u are gonna saw.
Step 3: Saw It! 1
If u r done with that Saw it.....
Step 4: Voila! 1
After u r done with sawing it should look like this.
Step 5: Mark It! 2
Now pick up the barrel that u sawed off and mark the place where u will cut(because u need flash hider).
Step 6: Saw It! 2
Now saw it....
Step 7: Voila! 2
The flash hider should look like this after u sawed it off.
Step 8: Sand Paper! 1
Now with sand paper soften the sawed part of flash hider and the gun.
Step 9: Attach It!
Now attach the flash hider to your gun with super glue and duct tape.
Step 10: Finished!
Now your M4 CQBR is finished. Now go out and get 'em Private!