Aero Precision X15 5.56 NATO AR-15 Custom Piston Rifle with BRN-4 HK416-Style Upper, B&T 9.5 in Handguard, SureFire SFMB-556 Brake, Geissele Two-Stage Trigger, 16 in Barrel
This custom AR-15 pairs an Aero Precision X15 lower with a Brownells BRN-4 HK416-style short-stroke piston upper for a proven, piston-driven setup in 5.56 NATO. It features a B&T AG 9.5 inch free-float handguard with a full-length, T-marked Picatinny top rail and a SureFire SFMB-556-1/2-28 muzzle brake. A Geissele two-stage SSE trigger and Geissele braided buffer spring with an H2 buffer round out the build. The rifle is in excellent condition and includes two 30-round magazines.
Condition
Overall Condition: Excellent condition, showing only faint signs of any prior use or handling.
Bore Condition: Excellent - Clean, mirror finish, no signs of wear.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: Light wear is present on the brass deflector. The bolt carrier group and chamber show minimal wear from prior use.
What’s Included
- 2x 30-round magazines
- SureFire SFMB-556-1/2-28 muzzle brake (installed)
- B&T AG BT-212544 Rev. 00 free-float handguard (installed)
- Flip-up front and rear iron sights (installed)
- Geissele two-stage trigger (installed)
Built on an Aero Precision X15 lower and a Brownells BRN-4 HK416-pattern upper, this rifle uses an HK-style short-stroke gas piston system for reliable, piston-driven operation. It is chambered in 5.56 NATO with a 30+1 capacity and ships with two 30-round magazines.
The front end is anchored by a 16 inch barrel with 1/2x28 threads and a factory-installed SureFire SFMB-556-1/2-28 muzzle brake. The brake is marked with NSN 1005-01-668-7486, providing a verifiable part reference for buyers who want specified components.
The B&T AG free-float handguard (BT-212544 Rev. 00) measures 9.5 inches and provides a full-length, T-marked Picatinny top rail. Flip-up front and rear iron sights are installed, giving immediate sighting capability.
A Geissele two-stage SSE trigger delivers a clean, predictable break. The recoil system combines a Geissele braided buffer spring with an H2 buffer. The rifle uses 7075-T6 aluminum receivers and includes a 6-position collapsible carbine stock with a stated length-of-pull range of 11.2–14.5 inches, plus a rubberized finger-groove pistol grip.