I just completed registering three Aero Precision lower receivers as pistol receivers. These are NOT special pistol marked receivers. I ordered two non anodized lowers directly from Aero Precision, and purchased one anodized receiver from Kaneohe Gun Shop's stock since Daniel was the FFL handling the transaction. I submitted the attached ATF letter, filled out the applications to acquire, then waited about 90 minutes while calls were made to Daniel and the ATF. They had to verify with Daniel that the lowers were never called rifles on any paper work. I'm not sure what they discussed with the ATF. The guy at the window told me if I don't hear from them with problems, then they will see me in two weeks. Well the two weeks went by, I picked up the permits, picked up the lowers and registered them today. I would hope this will make it easier for others to do the same. Since I did register one lower purchased from local stock, that should demonstrate any receiver can be registered as a pistol receiver as long as it was never registered as a rifle.