SKU: 156331
UPC: 810097509276
MPN: 55B8D86AB
The CMMG 55B8D86AB Dissent MK4 5.56x45mm NATO upper receiver is a left-side charging handle upper built for AR-platform rifles demanding non-standard ergonomics and proven reliability. Chambered in 5.56x45mm NATO, this 10.50" barreled upper delivers compact footprint performance ideal for close-quarters work, breaching, or confined-space operations where traditional right-side controls create handling inefficiencies.
The Dissent MK4 upper pairs a 10.50" 5.56 barrel with a zeroed blast compensator to manage muzzle energy and flash signature. The 9.60" M-LOK handguard provides modern accessory mounting capability across the forend, while the Picatinny end plate accepts standard optics and accessories. Finished in hardened Armor Black, the receiver is constructed for duty-grade durability. Weighing 5.21 lbs, this upper balances firepower with manageability in transitional environments.
This upper is designed for operators and shooters who run left-handed ergonomics, ambidextrous builds, or situational setups requiring charge handle access from the left side. The short barrel and compact profile suit CQB training, home defense staging, and duty carbines where velocity trade-offs are acceptable for handling speed. As an upper receiver only, it integrates with any compatible AR-15 lower receiver and bolt carrier group.
Left-side charging handle uppers remain a niche category, demanded primarily by left-handed shooters, ambidextrous operators, and teams optimizing non-standard engagement profiles. CMMG's commitment to alternative ergonomics makes this upper a direct solution for buyers seeking to avoid custom builds or secondary uppers.
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