This instructable will tell how to make a bb gun out of the nightfinder.
You have to remove the air restrictor and add lots of rubber bands.
You also need this 1x1 lego pillar.
Use the copper bb's. (not airsoft)
Remove the rubber head and stalk from a dart and insert the lego pillar with the square part sticking out.
Put it in the gun and tape it so it can't fall out.
Now you have a rather powerful nerf bb gun. If anyone can improve the accuracy please let me know because it has really bad aim.