Quoted:
Hey guys, I'm building my first AR. I have everything ordered, but then realized that I never ordered a buffer. Thats where i'm having mass confusion. I ordered this complete upper: https://www.hardenedarms.com/ecProduct_259 It has a carbine length gas system. I also ordered the following: Stock  http://www.midwayusa.com/product/518869/magpul-stock-moe-rifle-ar-15-lr-308-synthetic Extension tube http://www.midwayusa.com/product/489724/dpms-receiver-extension-buffer-tube-ar-15-a1-a2-stock And buffer spring http://www.midwayusa.com/product/191371/dpms-buffer-spring-ar-15-rifle  

I've looked around the forums quite a bit to get an answer, but I'm just not 100% positive. Do i want a rifle buffer, or a carbine buffer? After reading quite a bit, it sounds like I need a rifle buffer. Can I get a few of you to confirm this? I apologize, I'm brand new to building, and this just has me completely stumped...Thanks a ton!