Aero Precision’s M4E1 Stripped Lower Receiver delivers the strength and unique looks of a billet machined lower, with the lower cost, lighter weight, and easy parts compatibility of a forged lower. The M4E1 starts as an "enhanced" forging from extra-strong 7075 T6 aluminum that is precision machined to final dimensions for compatibility with all standard "mil-spec" AR-15 parts. As a bonus, the good-looking M4E1 has a streamlined profile, without the chunky appearance of many milled lowers.
Actually, the Aero Precision M4E1 Stripped Lower Receiver is not quite "stripped." Extra benefits include an integral triggerguard, which creates a more rigid, structurally sound receiver than a standard AR-15 lower, and also eliminates the risk of accidentally breaking off a triggerguard tab when working on the rifle. The enlarged triggerguard opening gives extra clearance so you can easily operate the trigger when wearing gloves.
The M4E1 comes with an easy-to-install threaded bolt catch roll pin that eliminates the risk of damaging the lower’s finish during installation (OK, you may be able to still do damage, but you’ll have to work hard at it!). Other features of the Aero Precision M4E1 stripped lower include: