I just used a butter knife behind one of the chest panels, to help push it out while I pushed the other panel in. Nine line up perfectly, now. like others have said, the gun is in three pieces -you just simply put the large handle in, and it slits sideways in the palm of his hand. Screwdriver and sandpaper won’t help with the springs- they are so stiff, they are almost just solid steel. They will eventually break the plastic or strip the screws. It’s better to remove them entirely, and replace them with weaker springs. The sample one at TFCon just “exploded” into pieces while the guy was messing with it.