The primary engineering feature we like on the M4E1 and M5E1 is the added rigidity and cooling of the barrel nut area. The barrel nut only has one job to do and that is hold the barrel in place unlike the traditional design which has the barrel nut serving dual roles of retaining the barrel and serving as a mounting platform for the handguard. The design and manufacturing process also make these upper receivers a favorite of ours. Forged 7075-T6 alloy will provide the perfect combination strength / weight for an accurate shooting rifle that will last a long time.
