XF50 SBR – Short Barrel PS90 with XF50 Tri-Rail Receiver
The XF50 SBR is a professionally built short barrel rifle based on the FN PS90 platform, upgraded with a billet tri-rail receiver by Imperial Arms Co. and a 10.4" barrel by CMMG. This build is engineered for reliability, modularity, and compliance — ideal for collectors, professionals, and serious enthusiasts.
Each rifle is assembled and engraved by Armory of Kings and transferred as a completed SBR. The engraving reads:
ARMORY OF KINGS
BOCA RATON, FL
What’s Included
- Factory FN PS90 rifle
- CMMG 10.4" Short Barrel – Replaces factory 16" barrel; maintains proper timing and floating delay system
- XF50 Tri-Rail Receiver – Manufactured by Imperial Arms Co.; replaces factory upper
- Installed choice of PS90 muzzle device
- CMMG 1/2" x 28 Thread Adapter (M12x1 LH to 1/2x28)
- CMMG P90 Style Flash Hider
- JMAC P90 KeyMo/KeyMicro Compensator
- NFA-compliant receiver engraving
- Fully built, test-fired, and prepared for Form 4 transfer
Note: Factory upper receiver and barrel are not included. They are replaced during the build with XF50 and CMMG components.
About the XF50 Tri-Rail Receiver
Manufactured by Imperial Arms Co., the XF50 Tri-Rail Receiver is machined from billet aluminum and offers three integrated 1913 Picatinny rails. This allows for easy attachment of optics, lights, and lasers, expanding the PS90’s capabilities while preserving reliability and internal alignment.
NFA Compliance
This is a completed short barrel rifle and must be transferred via ATF Form 4 to your FFL/SOT. An approved Form 4 and $200 tax stamp are required prior to shipping.
All NFA rules apply.
Optional Upgrades
- Choice of PS90-compatible muzzle devices
- Aftermarket charging handles, trigger and accessories sold separately
