Amend2 Modular Stock, For AR-15 MilSpec Buffer Tube, M-LOK Compatible, Lower Storage, Black A2AMSLOWSBLK One stock. Unlimited options. The Amend2 Modular Stock (AMS) provides users with a one stop shop for mission configurable stock accessories. Whether you need battery storage" a small compartment for your field notes" on-board cleaning kit" or an ultra light minimalist stock" the AMS can be configured to fit your mission requirements.