The Nerf surgefire is not reloading

If I recall correctly, the drum found on the Surgefire cannot be removed once installed, and it can only be reloaded by inserting the darts at the front of the blaster. There might be modifications to allow for the drum to be easily replaced, but I wasn't able to find one for you.

If you are talking about the darts not being able to enter the drum itself, I would try cleaning out the holes within the drum, making sure that there isn't any debris within the blaster's drum.