The Nerf Mega Centurion rifle does not have a breech loading port which would allow loading a single dart into the gun without using a magazine.
This is a problem for me because the magazine is difficult and slow to load.
This mod removes part of the left side of the rifle near the chamber to allow you to load a single dart.
Step 1: Draw
Use a felt-tipped marker to draw the loading port on the left side of the rifle. The right side cannot be used because there are two mounting screws on that side.
The port should be wide enough to easily fit a dart but not too wide: in the area you will be cutting there is a structural rib on the bottom and at the top there is a slide for the jam door (breech cover) that you don't want to interfere with.
Step 2: Drill
Drill holes at the 4 corners of the loading port that you have drawn and connect the 4 corners by drilling holes along the lines you have drawn. Use a small diameter bit and stay inside the lines.
Step 3: Cut
Use a utility knife to connect the holes you have drilled.
Step 4: Smooth
Use a wood rasp and the utility knife to smooth the edges of the loading port and make it only large enough to easily load the dart.
Step 5: Test
Insert the dart through the loading port to make sure it is correctly sized. Practice loading using your new loading port without a magazine in the rifle.