FN PS90 M-LOK Handguard (Gen 4)

Product Description

The Haga Defense Gen 4 M-LOK Handguard for the FN PS90 transforms approximately 6" of exposed barrel into functional space with M-LOK slots on the top, sides, and bottom for accessory mounting, improved forward grip positions, built-in hand-stop and a sleek tactical look. Crafted from durable nylon, this ultra-lightweight handguard (4.6 oz) enhances customization while keeping weight minimal.

Specifications

• Material: Durable MJF nylon
• Color: Black
• Weight: 4.6 oz
• Included: Handguard, mounting hardware
• Made in: USA

Compatibility and Installation Notes

• This Gen 4 handguard is engineered to fit all FN PS90 variants, including older (measuring approximately 31mm wide across the front of the receiver) and newer (33mm) receiver models, ensuring a perfect fit across the platform without the need for additional modifications.
• Standard variant has tight clearance—some side-mounted accessories may require shorter screws
• Standard variant does not accommodate suppressors under handguard—search "FN PS90 M-LOK Suppressor Handguard (Gen 4)" variant for suppressor use
• Field stripping remains tool-less and easy
• No permanent modifications required

Installation Instructions

1. Safety First: Before beginning installation, make sure the firearm is completely unloaded, the chamber is empty, and the safety is engaged. Remove the magazine, visually and physically inspect the chamber to confirm it is empty, and point the firearm in a safe direction at all times.
2. Remove the forwardmost screw and nut using a 3mm hex tool.
3. Test fit the included mounting blocks into the rectangular cavity on the front of the receiver. On newer guns the blocks should fit nice and snug. On older guns the blocks will fit loose and need to be adjusted. To do this use a ⅛" hex tool to back out the pre-installed nylon set screws a little at a time until a nice snug fit is achieved. Be careful when adjusting the set screws as they can easily be stripped. If you do strip out the set screw and can no longer turn it try using a T20 Torx bit instead of the included hex wrench.
4. While holding the mounting blocks in place, slide the new handguard onto the gun until the lower hole on the handguard lines up with the hole where the screw was removed on the receiver. The upper holes on the handguard should line up with the threaded inserts in the mounting blocks.
5. Install the lower screw and tighten up the thumb nut by hand.
6. Using a 4mm hex tool install the upper handguard screws. NOTE: If you have an older P90/PS90 there will be a gap between the handguard mounting tabs and the mounting blocks. If this is the case install the included washers (one on each side) between the mounting tabs and mounting blocks before installing the screws. Failure to use the washers when needed will create stress on the mounting tabs and could result in breakage.

ADDITIONAL NOTES

• If you notice some play/wiggle in the handguard try adjusting the mounting blocks to fit more tightly in the cavity on the receiver. If they have room to wiggle around your handguard will too.
• Mounting blocks can be secured using adhesive for an even more solid fit.
• In some instances there may be some play in the handguard even if installed correctly. If you look closely this can be caused by some play in the gun itself. If you are able to slide your upper receiver back and forth in the lower receiver while locked in place this may translate into some slight handguard movement.
• For field stripping remove the lower screw and thumb nut. The handguard can remain installed to the upper receiver during disassembly.