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CMMG
Overview
The CMMG Mk4 Banshee Upper Receiver Group is a complete assembly designed for the AR-15 platform, featuring a 12.5-inch barrel chambered in 5.56 NATO. This compact upper receiver is ideal for builders looking to create a versatile firearm that excels in both maneuverability and performance. It's commonly used in builds tailored for tactical applications or close-quarters engagements, where a shorter barrel length provides an advantage.
Specifications
CMMG MK4 Banshee Upper Receiver Group 5.56x45mm NATO 12.5in Armor Black
September 2026 on GunPartPicker
CMMG MK4 Banshee Upper Receiver Group 5.56x45mm NATO 12.5in Armor Black ranked #267 of the 615 upper receivers builders added on GunPartPicker in September 2026. Builders have been adding it to their builds on GunPartPicker since February 2026. All time, it ranks #200 of the 1,683 upper receivers builders have added.
Availability is good: it was in stock at one retailer or another nearly every day in September 2026, and today 2 of the 3 retailers we track have it in stock. It dipped to $700.24 at BattleHawk Armory for a stretch in September 2026, under its usual $738.73, so sales do come around. Buying today, the lowest price is $738.73 at GritR Sports, above September's low of $700.24, so a better deal may come back.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 37 retailers
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Build Configuration Breakdown
Aggregated and anonymized data showing how builders use this product
Gas SystemBased on real build data showing which gas system lengths builders use with this product.
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