Hello,
From the look of the picture, I would guess you are using the command "Lock Object On" to lock the object to the camera. I would recommend against using it. It can make objects appear "inside out" which kinda looks like what is happening in the picture. It also won't detect collision properly, lighting for the model will be a little different, there are a bunch of reasons. It's a good command for quick locking of content to the screen but not so great when things like the above occur. It doesn't actually position the object where you see it, it just sort of draws (renders) it there. The actual position and rotation of the object are where ever it was positioned with the position object command.
Now, if it actually is a problem with the scaling, depending on the rotation points of the limbs, the limbs can scale outward instead from the center as you mention. Depending on the situation this may not be an easy fix so before getting into that, take a look at this:
Locking Object with Math
Follow through the thread to understand the idea. The function should allow you to lock your weapon to the screen by actually positioning the weapon. I'm basing this suggestion on the look of the picture you included. It definitely looks like the inside out problem of
lock object on as opposed to mis-scaled limbs. If that doesn't help, we'll move onto the next step.
Enjoy your day.
