M4A1 GEN9/GEN10/GEN11 UPGRADED ALLOY TAIL / SPRING RETAINER + BEARING KIT PERFECT FIT : BEASTPRO UPGRADE

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  • $10.99
  • Regular price $19.99


They allow the spring to spin increasing RPS.

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M4A1 GEN9/GEN10/GEN11 UPGRADED ALLOY TAIL / SPRING RETAINER + BEARING KIT PERFECT FIT : BEASTPRO UPGRADE