How do you load powerline model 15xt?

Theres a slit going across the left side of the barrel with alittle half circle opening. Then theres alittle flap looking thing that rides along that slit...

Push that flap all the way back (towards the back/handle of the gun), and insert up to 15 bb's into that half a circle hole, then push that little tab forward until it doesn't move forward anymore. As you shoot that little tab will move forward (on its own) as its putting pressure on the remaining bb's to move forward. Hope this helps

Hole