Parent shaking when hit play in bge I have a character  with an empty object as parent with the hand bone. I use this empty to parent the guns and I have a gun inside of it, when play the animation the weapon stay static inside the empty just like I wanted, but, my problem is  when I hit P to play the game the don't stay static inside the empty object, the weapon keeps shaking inside the empty object. someone knows ho to fix it? what am I doing wrong? There's another better way to parent a gun to gun to the characters hand? thanks in advance.
I had a similar problem when tinkering with the BGE.  I had a rudimentary cannon and large sponge rubber shells so no one gets hurt.  The empty was used to move the shells out of the barrel .  It was too close to the barrel if I remember properly and would sort of tremble.  It was long time ago but I can go back into that project and even send it to you if you want.

Try removing the parentage, move the empty about a little, then re-parent it, see if the problem goes away...