ProMag RM-40 40rd AR-15 Magazine, Black Zytel, 5.56/.223

The ProMag RM-40 is a 40-round detachable magazine designed for AR-15 platform rifles chambered in .223 Rem / 5.56 NATO. The magazine features a DuPont Zytel polymer body and a patented anti-tilt roller follower for smooth feeding. It uses a heat-treated chrome silicon spring and is manufactured in the United States.

Key Specifications

• The capacity is 40 rounds.
• The cartridge compatibility is .223 Rem / 5.56 NATO.
• The body material is DuPont Zytel polymer.
• The finish is black.
• The magazine type is detachable.
• The follower uses a patented anti-tilt roller follower.
• The spring is formed from heat-treated chrome silicon wire.
• The country of origin is US.
• The overall length is 10.25.
• The weight is 0.45.

Built for extended use and straightforward maintenance, the RM-40 provides a high-capacity option for range sessions, training, or duty use where additional capacity is needed. Its roller follower and durable polymer construction are intended to reduce friction and resist wear during repeated loading cycles. This magazine is a practical spare or replacement for AR-15 owners who prioritize reliable feeding and long-term storage stability.