Hey guys! Recently, I bought a Matrix/Aim Top Pro-line M4A1 second handed from a friend for $50. The gun seems to be misfeeding very badly. Like, it doesn't feed at all. I installed an Echo 1 metal hop up (one piece) into it, and everything else is stock. The gun doesn't seem to feed. I'll tell you this, the outer barrel is bent a tiny tiny bit. You can only see it with the handguards on. The inner barrel is fine, my thoughts was maybe the barrel is forcing the hop to sit incorrectly (it requires a ton of force to seat in, like hit it with a hammer force). when the trigger is pulled, the gearbox does its cycle, but the red air nozzle that pushes the air into the hop up chamber sticks out like half a centimeter which prevents BBs from entering the hop up chamber. I can push the nozzle back a tiny bit and it will feed a BB but then it just does the same thing, not fully retracting out of the hop up chamber. I had a professional shim and lubricate the gearbox twice, and it runs smooth while it's out of the gun itself, so my conclusion is could the barrel be causing all of this? I don't want to spend $30 plus tax to get a new barrel and find out it doesnt fix the problem. Thank you very much. You're probably wondering why I bought a broken gun for my first gun.... Well let's keep it this way. Your first car is never going to be a brand new car (as a teenager anyway). Chances are you'll buy an old car and fix it up as you go. Same with houses. Chances are you wouldn't buy a brand new, 2012 or 2011 built house for your first house unless you are really wealthy (I am not so let's keep it simple). Back to the Airsoft. Besides, I bought the gun for $50!! It has a steel body with M4A1 trademarks and a marine logo (by Matrix too). The gun retails for $240 and the body retails for $30-$50 so it's a good deal. So please any help will be fabulous! Feel free to ask questions, I think I made this seem confusing. Thanks so Much!!!