TacFire SSRK556LPK Lower Parts Kit — 16-inch 5.56/.223

Description

The TacFire SSRK556LPK is an unassembled AR-platform lower parts and rifle build kit configured for 5.56/.223 use. The kit ships with a 16-inch M4 contour 5.56 NATO barrel finished in nitride, along with a selection of upper and lower components suitable for assembling an AR-style semi-automatic rifle. Components include aluminum and steel parts sized to common AR specifications for straightforward assembly by a qualified technician or builder.

Key Specifications

• The barrel is a 16-inch 5.56 NATO M4 contour finished in nitride for corrosion resistance.
• The muzzle uses a 1/2″-28 tpi thread pattern and ships with a birdcage flash hider and crush washer.
• The handguard is a 15-inch M-LOK free-float design for accessory mounting and improved rigidity.
• The upper included is a stripped billet AR-15 upper receiver listed as compatible with 5.56/.223/.300 AAC in the kit description.
• The charging handle is Mil-Spec aluminum with a steel latch as specified in the kit contents.
• The kit includes an AR-15 USA-made lower parts kit and an A2-style black pistol grip.
• The buffer system includes an aluminum buffer tube and a 3 oz AR-15 buffer with spring.
• The trigger supplied is listed as Mil-Spec in the product attributes.
• The overall finish for applicable components is Black Nitride per the product attributes.

This TacFire SSRK556LPK assembly kit brings together key components for a practical, service-oriented AR build: a nitride-treated 16-inch M4 contour barrel, a long M-LOK handguard, billet upper, and Mil-Spec controls and internals. The kit is suited for builders who want a coherent parts set that adheres to common AR specifications and finishes, and it offers the core components needed to assemble a dependable semi-automatic AR-platform rifle when combined with the appropriate lower receiver and compliant assembly practices.