ProMag RM40SL 40rd AR-15 Magazine — 5.56 NATO, Black

The ProMag RM40SL is a 40-round detachable magazine designed for AR-15 rifles chambered in .223 Remington / 5.56x45mm NATO. It pairs a lightweight DuPont Zytel polymer body with over-molded stamped steel feed lips and a steel-lined catch for reinforced feeding surfaces. The magazine uses a patented anti-tilt roller follower and a spring formed from heat-treated chrome silicon wire for consistent function. Built in the USA, the RM40SL is intended for range use, training, and competitive shooting.

Key Specifications

• The capacity is 40 rounds.
• Compatible with AR-15 platforms.
• Chambering supported is .223 Rem / 5.56 NATO.
• The magazine body is constructed of DuPont Zytel polymer.
• Feed lips and magazine catch are over-molded stamped steel.
• Includes a patented anti-tilt roller follower.
• The spring is formed from heat-treated chrome silicon wire.
• The finish is black.
• Manufactured in the USA.

Combining polymer weight savings with steel reinforcement where it matters, the RM40SL is designed to provide reliable feeding and repeatable performance for shooters who regularly train, compete, or practice on the range. Its roller follower and quality spring construction aim to reduce common feeding issues while keeping handling familiar to AR-15 users.