The Aero Precision EPC-9 9/40 Threaded Assembled Upper Receiver with LRBHO (APAR620201AC) is the perfect addition to any AR9 build. Including a last-round bolt hold-open mechanism and compatible with most standard AR15 barrel nut and handguard combinations this upper receiver will help take your pistol caliber build to the next level.

Features:

• Last round bolt hold-open mechanism
• Accepts most AR15 compatible barrel nuts and handguards
• Dimple above threads to allow for proper handguard timing
• Standard AR15 takedown/pivot pin lug pattern
• Machined from custom forged 7075-T6 aluminum
• Laser engraved T-marks
• Weight: 7 oz

Includes:

• Upper Receiver
• Pre-installed last round bolt hold open assembly

Note: The EPC last round bolt hold open is ONLY compatible with appropriate GLOCK® pattern magazines.