Building my first AR10 and got receiver parts from the local gun shop. Was going to go with an Aero Precision stripped lower and install parts as needed as I wanted the Hiperfire ECLipse trigger group, ERGO pistol grip and Luth AR stock. Salesman said it would be cheaper to just buy a complete lower then a stripped lower and all the parts. Didn't think it through completely and ended up with a complete CARBINE lower. Here's my issue: It has the carbine buffer tube but I ordered a 20" barrel. Will the carbine buffer tube work with a 20"? Or should I get a rifle buffer tube for it?