I live in PA and bought a S&W M&P AR a few weeks ago. It was $200 bucks cheaper than anywhere but its NY legal. Only a 10rnd mag and a pinned stock. I already bought 30rnd Pmags but want to know if the stock can be adjusted or if I need to just get a new stock. It looks identical to an adjusting stock execpt it has a tiny pin in the front of it. I'm sure I can remove the pin but I don"t know if it will still adjust properly. The trigger you squeeze to slide it does not move at all. I removed the allen screw holding it on and I dont see any kind of spring in it. Has anyone dealt with this before?