I've set up a player with a few bones. Arms and head moves with the mouse(angle). He got a weapon that is also a bone. If I want to attach something to anything that belongs to the bone behavior(set position to "sprite") and I move via platform behavior too fast, it lags. If you jump, the bullets lags a few pixels above or underneath, depends if you jumping or falling.
Here is an example: https://dl.dropbox.com/u/26932498/bone_behavior_lag.cap
The torso is attached to the hitbox, the arm is attached to the torso. The weapon is attached to the arm. I can fix the lag, creating the bullets on an imagepoint from the hitbox, but in my engine, the arm is moving with the mouse and have lots of functions how to behave etc(the cap here is just a fast demo I created to made my point clear)..., so the imagepoint of the weapon is needed, because the weapon is moving with the mouse.
Is there any way to fix that lag between the weapon and the spawned bullets if you move to fast or jump?