Aero Precision M4E1 Stripped Lower Receiver (AR15, "Cal Multi" Marked)
The Aero Precision M4E1 Stripped Lower Receiver is an enhanced-forged AR15 lower built from machined 7075-T6 aluminum. The M4E1 design blends billet-style exterior lines with standard AR15 parts compatibility.
Key M4E1 features include an integrated trigger guard, a flared magwell, a threaded bolt catch pin design for simplified installation, an upper receiver tensioning screw provision, and a rear takedown pin detent channel threaded for a 4-40 set screw. This unit includes the original box.