MSAR XM17-E4 .223 Rem Bullpup Rifle – 18-inch Fluted Barrel, Short-Stroke Piston, AR-15 Mag Compatible, Pinned/Welded PWS FSC 556
This MSAR XM17-E4 is a U.S.-made bullpup in excellent condition, built around a short-stroke gas piston system and the E4/NATO magazine interface that accepts AR-15/STANAG magazines. It features an 18-inch fluted barrel, a non-reciprocating charging handle, and a flattop Picatinny rail with additional accessory rails. Upgrades include a pinned and welded PWS FSC 556 compensator/brake for state compliance, an upgraded factory magazine catch, and an installed vertical foregrip. It comes with useful MSAR spares including a small parts kit, a recoil spring set, two spare gas pistons, and a spare gas plug.
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 Details: The PWS FSC 556 compensator/brake is pinned and welded. Overall presentation is clean with only mild handling wear.
What’s Included
- 1x Amend2 10-round magazine (marked 6.5 Grendel)
- Flip-up iron sights (installed)
- Vertical foregrip (installed)
- MSAR Picatinny accessory rail sections (installed)
- PWS FSC 556 compensator/brake, pinned/welded (installed)
- MSAR small parts kit (bagged spares)
- MSAR recoil spring set (bagged spares)
- MSAR gas piston(s) (spare)
- MSAR gas plug (spare)
- QD sling swivels (2x installed)
The XM17-E4/NATO configuration is designed to run AR-15/STANAG magazines and uses a short-stroke gas piston action. It ejects to the right and includes a left-side port cover. Controls include a non-reciprocating charging handle on the left-top of the receiver and an upgraded factory magazine catch for confident magazine changes.
The 18-inch fluted barrel balances compact bullpup handling with full-length performance. At the gas block, an adjustable MSAR gas plug/regulator lets you tune the system. The muzzle is capped with a PWS FSC 556 compensator/brake that is pinned and welded for state compliance.
A flattop Picatinny top rail provides mounting for sights or accessories, complemented by additional side and bottom accessory rails. MSAR rail sections are installed, and the rifle ships with flip-up front and rear iron sights plus a vertical foregrip.
The polymer bullpup stock integrates the trigger guard and a rear QD sling attachment loop, delivering a measured 15.0-inch length of pull. The aluminum-alloy receiver is marked UNITED STATES OF AMERICA / XM17-E4 / CAL .223 / BRADFORD, PA, underscoring its U.S. manufacture.
This rifle arrives with practical MSAR extras: a small parts kit, an MSAR recoil spring set, two spare MSAR gas pistons, and a spare MSAR gas plug. The seller notes a 10+1 capacity when used with a 10-round AR-15/.223 magazine. Included magazine is an Amend2 10-round unit marked 6.5 Grendel.