AERO Precision just announced that they are adding some really great looking 300BLK uppers to the website. These uppers are built off of the new M4E1 upper receiver which features an integrated rail mount interface, meaning the rail mouths directly to the upper receiver and not to a barrel nut for increased strength. Barrels are made from 4150 CMV and have a QPQ (Nitride) surface treatment inside and out. You can purchase an 8″ or 10″ M4E1 300BLK upper receiver with your choice of multiple different rail types and lengths starting at just $396. Take a look over at www.AEROPrecisionUSA.com.