I'm looking at buying a 2001 model SAR1, when I was looking it over I pulled the charging handle back and it hung up when going back in unless I pulled it all the way back then let it go. The guy said he's had a few SARS and all of them have done that. He said the that regardless of where the magazine is from the charging handle stays open after the last bullet is shot. None of my other AKs do this, is what he is telling me true?