Hey there guys. I am new to airsoft and I have bought a JG AUG. I knew that it is a bad gun for a beginner but it is my favourite weapon and i wanted it so bad. Anyway, from the first time I got it it started behaving a little weird. Let me explain. Even before using the gun for a match, I bought a LiPo battery (7.4) for the gun and changed the tamiya connectors to deans. I went to my first match and it was a little cold (around 0 to 5 degrees C). The hop up started under performing and even was double feeding some of the time or not feeding at all. The hop up was only performing well when i used full-auto, slowly gaining maximum range with each shot, but after a while (of not shooting) it would under perform again. Some guy at the field told me that it was because of the cold. Some other guy mentioned that it might be a piston or cylinder problem, or a cylcling problem. I disassembled and reassembled the hop up and at the next match the same thing was happening except the feeding problems which were corrected for some reason. I knew those guns have a hop up problem from the get go so I purchased a Lonex aug metal hop up and a new plastic nozzle with an O-ring inside it, plus a metallic cylinder head with double O-ring (even though the stock one seemed OK) and replaced the stock ones. Also I shimmed the gears and now I use a maple leaf bucking and nub. I went today to test the gun for a few rounds and the shots were not going very far. After i increased the hop up the shots went even shorter and with very low speed. I even replaced the stock barrel with a new guarder one (both are 509mm) but nothing has improved. Anyone has any idea what is exactly happening with the gun? I will keed you updated with more info. I will probably test the gun again in 2 days.