Ambi Charge Block Kit MCX After the success of the MPX Ambidextrous Charge Handle and Lifter Block, our team at Next Level Armament was immediately asked 'what about the MCX?' You asked, we responded! Based upon one of the industries best ambidextrous charge handle design that includes models for the AR15 rifle, the AR10, the M&P 15-22 and the Sig MPX, the MCX Ambi Charge Handle was born. The MCX uses a molded plastic OEM spring plate. Over time, the plate becomes brittle and can break. We manufacture our spring plate from solid 4140PH steel then Nextride coated it for a long lasting, reliable, and durable replacement for the OEM molded plastic spring plate. *NOTE: Sig redesigned the spring plate with the new Virtus and Rattler MCX models. This spring plate only works with the previous MCX models without the pinned block . The MCX ambi charge handle remains compatible with all MCX models and is available as a stand-alone product.