I bought the one you are talking about as well and I will have to get a professional to do the fitting for me. I bought it without really doing much research into the set. I just saw 5.5mm folding stock and trunnion at work and bought it without reading the discretion because I was busy. So that is one is on me and I own it lol. As to the quality of the metal, I can not speak but it is not a true ak 100 series spec. Getting started on piecing an AK build together is a learning experience and now those lessons cost a lot more than they use to. I am looking for a 100 5.5mm trunnion and don't want to make the same mistake again. As to people being rude, I don't know why that happens. Everyone is new to something when they first start. I have never met a person born with all the knowledge the world has had to offer but apparently, the internet is full of them. I just assume that their life is miserable or they have a micropenis.