Lots of great info here, but haven't run across many posters with SBR's. I am considering building a SBR AR. Granted I would either build or buy lower reciever and probably buy SBR upper complete. Any insights or suggestions?
Check your state laws. You're in Texas, so you shouldn't have many issues. Most likely you will have to purchase a $200 (may vary) tax stamp and register the receiver's SN with your state's Bureau of Investigation. The short upper cannot be placed upon another receiver.
It IS worth the hassle though, they are alot of fun!