Can anyone tell me some info on the AK bayonet? I just got one and have a question on it. About 3 inches from the front of the blade tip is a rounded hole. What's that for? Also, on the oposite side of where you slide the barrel onto there is a 'hook'. It's on the same side as the saraded edge. And on the sheath...At the end or bottom of it , what is this? One part looks like a "T". Any help will be appreciated. Thanks.