@TRUBL will the ESSB and DBRS work with the Angstadt 9mm upper receiver? I am building my first AR pistol and I am looking at the full Taccom setup with the Extreme barrel, ESSB and DBRS. Will there be any issues running this with the dedicated 9mm Glock upper and lower from Angstadt Arms? Mostly curious if the smaller ejection port would cause problems with the ESSB.