ProMag RM40 40rd AR-15 Roller Follower Magazine 5.56x45mm

The ProMag RM40 is a 40-round detachable magazine designed for the AR-15 platform. It uses a patented anti-tilt roller follower and a DuPont Zytel polymer body to promote smooth feeding. The magazine spring is formed from heat-treated chrome silicon wire and the unit is made in the US. This magazine is intended as a replacement or spare for compatible .223 Rem/5.56 NATO AR-15 rifles.

Key Specifications

• The magazine capacity is 40 rounds.
• Compatible with .223 Rem/5.56 NATO cartridges.
• Designed to fit the AR-15 platform.
• Magazine body constructed from DuPont Zytel Polymer.
• The exterior finish is Black.
• Features a patented Anti-Tilt Roller Follower for reduced friction during feed.
• The magazine spring is formed from heat-treated chrome silicon wire.
• Country of origin listed as US.
• Listed overall length is 10.25, width 2.5, and height 1.25 as provided.
• Product type is Detachable.

Built as a practical, serviceable spare or replacement, the RM40 blends high-capacity utility with low-friction feeding courtesy of the roller follower and robust spring. Its polymer construction keeps weight down while providing durable everyday handling. For users who keep magazines loaded for storage, the spring and materials are specified for long-term readiness. The RM40 is a straightforward, no-nonsense magazine option for AR-15 owners seeking a reliable 40-round capacity without unnecessary complexity.