The MK2 buffer (3.8oz) is offered as a stand alone option to tune AR pattern rifles that are already equipped with the MK2 recoil mitigation system. Allows fine tuning for optimal reliability and ejection pattern on rifles that are over gassed whether suppressed or unsuppressed. NOTE: only to be used as an upgrade to AR pattern rifles already using the MK2 Recoil Mitigation System.Features :Lessens felt recoil, without compromising reliabilityProvides a more consistent carrier velocity, which can aid in accuracy, reliability over conventional carbine buffer systemIncreased internal counterweight travel reduces bolt bounceUses a M16A4 rifle spring with more spring coils than M4 carbine, increases consistency and widens operating envelopeInternal spring to reduce noise of counter weight shifting and ensure more consistent weight placement