FN PS90 Rifle | 10.4" Barrel Conversion by Armory of Kings
ATF UPDATE | EFFECTIVE OCTOBER 9, 2026
A new opportunity for PS90 enthusiasts! ATF's updated enforcement guidance provides a new pathway for eligible customers to purchase professionally converted Short Barrel Rifles without the traditional NFA approval process, subject to the scope and continued applicability of that guidance.
Under the current enforcement policy, covered SBR transactions may proceed without the traditional $200 NFA tax stamp or Form 4 approval. Standard firearm transfer requirements, background checks, and applicable state and local laws continue to apply.
Important Regulatory Notice: The October 9, 2026 ATF guidance reflects the agency's current enforcement policy and does not change the underlying federal law. This policy is subject to future regulatory, legislative, or judicial changes. All purchases, shipments, and transfers remain subject to applicable laws and requirements in effect at the time of fulfillment. Armory of Kings reserves the right to adjust or suspend fulfillment as necessary to maintain regulatory compliance.
Brand New Factory FN PS90 with Professional 10.4" Barrel Conversion
Start with a brand new factory FN PS90, professionally upgraded by Armory of Kings with a CMMG 10.4" barrel and your choice of six muzzle devices.
Each rifle begins as a genuine factory FN PS90 with its original 16" barrel. Our professional conversion replaces the factory barrel with a compact 10.4" configuration while preserving the PS90's unique operating characteristics.
The original factory 16" barrel and shroud are included whenever they can be removed intact, giving you the original components alongside your professionally converted rifle.
What's Included:
- Brand new factory FN PS90 rifle
- Professional barrel conversion by Armory of Kings
- Installed CMMG 10.4" Chrome Moly Barrel
- Your choice of one professionally installed muzzle device:
- Factory magazine (30 or 50 round, depending on availability and applicable law), box, manual, and accessories
- Original factory 16" barrel and shroud, whenever they can be removed intact
Please Note: Removal of the original barrel and shroud can sometimes result in irreversible damage. Original components are included only when they can be recovered intact.
Choosing the Right Muzzle Device:
Customize your PS90 conversion with the muzzle device that best fits your intended configuration:
- CMMG 1/2" x 28 Thread Adapter provides a versatile mounting solution for compatible suppressors and muzzle devices using standard 1/2x28 threads.
- CMMG P90 Style Flash Hider recreates the classic military P90 appearance. This option is not intended for suppressor mounting.
- GSL P90/PS90 Flash Hider features the GSL Bi Lock mounting interface for compatible GSL suppressors.
- JMAC P90 KeyMo/KeyMicro Compensator provides a mounting solution for compatible suppressors using the Dead Air KeyMo system.
- CMMG ZEROED RBB PS90 Muzzle Brake with Plan B Adapter combines a muzzle brake with a Plan B compatible suppressor mounting interface.
- 360HD Micro HUB for P90/PS90 10.4" Barrels combines the muzzle device and 1.375x24 HUB mounting interface into a single component. This integrated design reduces unnecessary thread stacking while preserving the PS90's floating barrel operation.
Suppressor Compatibility: Always verify that your selected muzzle device is compatible with your suppressor and mounting system before use.
Why Choose a 10.4" Barrel Conversion?
The FN PS90 is already known for its compact bullpup design, excellent balance, and unique 5.7x28mm chambering. Replacing the factory 16" barrel with a CMMG 10.4" barrel creates an even more compact configuration while retaining the familiar handling characteristics of the original platform.
The shorter barrel also provides a convenient foundation for compatible suppressor configurations without the added length of the original factory barrel.
About the CMMG 10.4" Barrel:
Our conversion features a CMMG 10.4" chrome moly barrel, professionally installed by Armory of Kings. The barrel features a 1:9 twist rate and is designed specifically for the FN PS90 platform.
Proper installation maintains the necessary barrel movement and float that are essential to the PS90's delayed blowback operating system.
Professional Conversion by Armory of Kings:
Every conversion is performed by Armory of Kings, a licensed firearms manufacturer specializing in the FN PS90 platform.
We begin with a brand new factory FN PS90, remove the original 16" barrel assembly, install the CMMG 10.4" barrel, and fit your selected muzzle device. The completed rifle is prepared for shipment to an eligible receiving FFL, subject to applicable transfer requirements.
Unlike a customer supplied conversion service, this package includes the complete factory FN PS90 rifle, barrel, muzzle device, and professional installation.
ATF Requirements and Firearm Transfers:
ATF guidance effective October 9, 2026 addresses enforcement of specified National Firearms Act requirements for Short Barrel Rifles. Eligible transactions are subject to the terms of that guidance and all other applicable legal requirements.
- The current enforcement guidance provides relief from specified NFA registration, tax stamp, and approval requirements for covered transactions.
- Additional NFA marking requirements are subject to the scope of the current guidance. Other applicable firearm identification requirements remain in effect.
- The completed rifle is shipped only to an eligible receiving FFL when the transfer is legally permitted.
- Applicable ATF Form 4473, background check, and dealer transfer requirements remain in effect.
- State and local laws governing Short Barrel Rifles continue to apply.
- All shipments and transfers are subject to the legal requirements in effect at the time of fulfillment.
Important: The completed firearm is classified as a Short Barrel Rifle because the installed barrel measures less than 16 inches. Including the original factory barrel does not change this classification. The current ATF enforcement policy does not guarantee future treatment, registration eligibility, or grandfather protection if the policy changes.
Suppressor Ready with Multiple Mounting Options:
Choose from six muzzle device configurations, including traditional thread adapters, dedicated suppressor mounting systems, and an integrated HUB mounting solution.
Whether you prefer a classic P90 appearance or a compatible suppressor mounting interface, the available options allow you to select the configuration that best fits your needs.
Additional Resources:
- Explore our complete PS90 muzzle device selection.
Start with the legendary factory FN PS90 and let Armory of Kings handle the conversion. Choose your muzzle device and order your professionally converted 10.4" PS90 today!
Frequently Asked Questions (FAQ)
Is this a brand new factory FN PS90?
Yes. Every package begins with a brand new factory FN PS90 rifle. Armory of Kings professionally replaces the original 16" barrel with a CMMG 10.4" barrel and installs your selected muzzle device before shipment.
Is this a factory FN short barrel rifle?
No. This is a genuine factory FN PS90 rifle that has been professionally converted to a 10.4" short barrel configuration by Armory of Kings. FN America does not perform the conversion.
What is included with my PS90 conversion package?
Your package includes a brand new FN PS90 rifle, installed CMMG 10.4" barrel, your choice of one of six muzzle devices, factory magazine, box, manual, and accessories. The original 16" barrel and shroud are also included whenever they can be removed intact.
Do I receive the original 16" barrel and shroud?
Yes, whenever they can be removed intact. Occasionally, the removal process can cause irreversible damage to the original components. Their return cannot be guaranteed.
Is the completed rifle considered an SBR?
Yes. Although the package begins as a factory 16" FN PS90, the completed rifle is classified as a Short Barrel Rifle because the installed barrel measures 10.4".
Do I need a $200 tax stamp or ATF Form 4?
ATF's October 9, 2026 enforcement guidance provides relief from certain traditional NFA requirements for covered Short Barrel Rifle transactions. Eligibility and transfer procedures depend on the guidance in effect at the time of fulfillment, along with applicable federal, state, and local laws.
How will my rifle be transferred?
Armory of Kings completes the barrel conversion before shipment. The finished rifle is shipped to an eligible receiving FFL when permitted under applicable law. Required dealer paperwork, background checks, and any applicable approvals must be completed before delivery.
Can I attach a suppressor?
Yes. We offer several muzzle device options designed for compatible suppressor mounting systems, including 1/2x28, GSL Bi Lock, KeyMo, Plan B, and HUB interfaces. Compatibility depends on your specific suppressor and mounting configuration.
Who performs the barrel conversion?
Every conversion is performed by Armory of Kings, a licensed firearms manufacturer with extensive experience working on the FN PS90 platform.
Can ATF requirements change after I place my order?
Yes. The current ATF guidance is an enforcement policy rather than a permanent change to federal law. If regulatory requirements change before fulfillment, we may need to adjust or suspend processing to ensure your order remains compliant with applicable law.
Does the barrel conversion affect the FN factory warranty?
Yes. Converting the FN PS90 into a Short Barrel Rifle voids the factory warranty provided by FN America. Armory of Kings does not provide a warranty on the complete rifle. However, we provide limited support on the installed barrel and muzzle device to ensure proper function upon delivery.
