Excellent upper receiver - Precision Reflex AR-15 Flat Top Upper Receivers - Striped

Nothing wrong with this PRI upper; it's a quality forged receiver and rather than white laser-etched T-marks shown in the picture, mine actually had colorless engraved ones, which I prefer. The pin tolerances for these uppers are mil-spec, and tolerance stacking between an upper and a lower can lead to a setup which might feel more loose than desired, as was seemingly the issue with one reviewer. If you're looking for a flawless lockup between receivers with zero wiggle, I would suggest an upper which has been specifically designed with tighter pin hole tolerances. As for anyone else, this upper is well made, by a company with a proven track record.