weird rotation with camera (no code issue)

Hello, I have a camera with 3 child game objects (pistol, rifle, shotgun)
within each, I have a gameobject called “aimobject”, and within that is the gameobject with the mesh.For some reason, when I look up or down with the camera with the rifle, it doesn’t seem to rotate on track with the camera, it kind of rotates on it’s own. (it’s hard to explain). Like, it kind of sways in the opposite direction… I thought it had to do with Apply → scale, but that didn’t seem to change anything. It doesn’t seem to be a Unity issue either. I am using Blender, is something wrong with the rotation/location or orientation?

Argh!! I spend two days sweating over this, and the mesh was not set to the proper layer to render in the correct camera! The whole time it’s been disconnected. Thanks for all your help…I would’ve been on a wild goose chase in blender! thanks again!