My buddy gave me a new,in the box, Yugo SKS. It was bought approx10-15 years ago and has never been fired, let alone cleaned!! He wants me to clean it up, and get it ready for some plinking. I know all about cosmoline and getting it clean,etc,, but it has the grenade launcher attachment on it, and I was reading there's a switch or button you use to put it into single shot mode for the launcher. Where is this button or switch located. I'm still cleaning the bore, receiver, and barrel, so I don't need an answer that fast.. I was just wondering where the heck it is. My son's Norinko of course doesn't have one. Any help or advise is truly appreciated. This rifle is a beauty, not a scratch on the wood or metal anywhere, and the parts I have already cleaned just shine!!!