Did you just get a Retaliator? Wanna know how to make it look sexy like a certain M4A1?..... Is that a yes? ALL RIGHT! Let's do this thingamabobber! Oh yeah, by the way. I forgot some pictures about the tools.

Step 1: What You Need I Guess..

Retaliator, (obviously)
any stock of your desire,
the barrel, an extra barrel piece, (could be from a broken Nerf gun)
a dremel or a little saw,
scissors,
orange duck tape (quack, quack!)
some white shoelace, (or blue shoelace if you have a blue Retaliator)
and the banana mag. (yes, a literal banana you monkey)
lighter (optional)
Nerf red dot sight (optional)
Nerf Retaliator grip (optional)

Step 2: Cutting!

Take the extra barrel piece and cut 3 inches off. The image above is the result.

Step 3: Unscrew the Barrel!

Watch a video about extending the barrel piece 'cause it's hard for me to explain. Sorry! :(

Step 4: Make Use of That 3 Inch Piece!

After watching that video and doing what it said you'll probably notice there's and empty area. THAT'S where this little 3 inch barrel piece comes in handy! Just put that piece like it shows in the picture.

Step 5: Might Wanna Add Some Tape.

After pushing the 3 inch piece all the way in UNLESS you made it perfect you'll need to tape the two pieces together. Orange, maybe?

Step 6: Screw the Barrel Back Together!

After screwing the barrel back together It kinda splits apart at the front, this is where you apply the white shoelace! (or blue shoelace!) You want to wrap it TIGHTLY around the area shown. After wrapping it tightly around the barrel burn the excess shoelace with a lighter. (or cut it)

Step 7: Add Those Attatchments to Your Gun!

Simple, put on the barrel.
Install stock.
Insert mag joke here.

Step 8: ENJOY!

Don't be bored, enjoy your M4!

Step 9: Do Keep in Mind.

Aplying the shoelace will create some difficulty removing/adding underbarrel attatchments.

Let me know what you think!
Have fun in outside/inside Nerf wars!