Re: AK-47 barell
Depends on if you want to remove just the barrel or the barrel and the barrel trunnion. The trunnion is pinned and riveted to the receiver, then the barrel is pressed in and pinned.
To remove just the barrel, you would need to drift out the barrel pin (usually VERY tight) then press out the barrel. This will require a hydraulic press and some ingenuity since the force will be applied at a slight angle.
If you are replacing a barrel, remember that Chinese barrels are narrower (19mm) than European barrels (23mm).
The autonomic nervous system provides for involuntary muscle function - the work of breathing, digestion, and so forth. On some folks, that's a pure waste of ingenuity.