M-Lok Screw Set 21 piece

Overview

This 21-piece M-Lok Screw Set is a spares and repair kit for anyone running M-Lok handguards, rail sections, bipod mounts or accessory attachment points on a modern sporting rifle or tactical shotgun. M-Lok, developed by Magpul as a free-to-license standard, has become the default slotted-rail interface on most current handguards because it drops weight and bulk compared with a full-length Picatinny rail while still giving a hard mechanical lock for accessories. The problem this kit solves is a simple but common one: the small hex-drive screws and T-nuts that clamp accessories into the M-Lok slots are easy to lose during a strip-down, and a rifle missing even one screw cannot mount that rail section securely.

Because this is sold under Various Brands rather than a single manufacturer's part number, it sits in the market as a universal, budget-friendly alternative to buying a single manufacturer's proprietary replacement pack, such as Magpul's own MAG615 T-Nut Replacement Set. The trade-off buyers should understand is that fit and finish vary between production runs, so it pays to test a couple of screws in the actual handguard before relying on the whole set. What makes a 21-piece set attractive is the quantity: most shooters only ever lose one or two screws at a time, so a set this size effectively becomes a lifetime supply of spares for a home armoury with two or three M-Lok-equipped rifles.

Key Features

• Twenty-one individual screws and matching T-nuts cover multiple mounting jobs at once, so a lost screw from a bipod stud, sling mount or offset rail section can be replaced immediately without a trip back to the gun shop.
• The T-nut design seats inside the M-Lok slot and spreads clamping load across the polymer or aluminium handguard wall, which stops a single screw point from crushing or stripping the slot over repeated mount-and-remove cycles.
• A black oxide or anodised finish on the steel hardware resists surface corrosion from handling oils, sweat and typical South African outdoor humidity, keeping the screws turning freely in storage.
• Hex socket, or Allen-key, heads keep the screw profile low so an installed accessory sits flush against the rail without a raised screw head snagging on slings, spare mags or clothing.
• Because the set is not tied to one accessory brand, it works across bipods, QD sling mounts, offset rails, foregrips and vertical grips from different manufacturers, provided they use the standard M-Lok slot dimension.
• The mixed screw lengths in the set cover thinner polymer handguards as well as thicker aluminium free-float forends, reducing the chance of a screw bottoming out before it clamps the T-nut tight.

Technical Specifications

Materials & Construction

The screws and T-nuts in a set like this are almost always cut from alloy steel rather than stainless, which is why the black oxide or anodised coating matters: bare steel hardware left in a damp range bag will show surface rust within weeks. The T-nuts use a cam profile that rotates into the M-Lok slot and locks against the inner wall of the handguard when the screw is torqued down, spreading the clamping force over a wider bearing surface than a screw threading directly into polymer would. This is the same basic principle Magpul uses on its own genuine hardware, though generic sets vary in how tightly the cam tolerances are held, which is the main quality difference between a branded and an unbranded kit.

Fit & Compatibility

This hardware fits any handguard, forend or rail section cut to the official M-Lok slot pattern, which covers the vast majority of AR-15, AR-10 and modern bolt-action chassis handguards sold in South Africa, along with M-Lok bipod studs, QD sling mounts, offset light mounts and vertical grips. It is not compatible with KeyMod slots, which use a different hole-and-slot shape, nor with plain Picatinny rail, which clamps with cross-bolts rather than T-nuts. Because thread and length standards are not perfectly uniform across every M-Lok accessory maker, it is worth test-fitting one screw and nut before committing an accessory to the rifle, especially on thinner carbon-fibre or polymer handguards where an over-length screw can bottom out against the bore.

In the Box

A single pack contains 21 pieces made up of a mix of screws, matching T-nuts and, on most generic sets of this size, a small hex key for installation. Quantities of each screw length are usually split roughly evenly so the set covers both thin and thick handguard walls rather than being biased toward one accessory type.

FAQ

Will this fit my Magpul MOE handguard? No, MOE uses a different slot system to M-Lok and needs its own adaptor hardware or MOE-specific screws.

Can I use these on a bipod stud? Yes, provided the stud or adaptor is cut for M-Lok, these screws and T-nuts will clamp it the same way a factory bipod mount does.

Do I need thread locker? A drop of medium-strength thread locker is worth adding on any screw that sees regular recoil, since bare metal-to-metal threads can work loose over a few hundred rounds.

Why does the pack have mixed lengths instead of one size? Handguard wall thickness varies between makes, so a longer screw is needed on a thick aluminium free-float rail than on a slim polymer handguard; the mixed set covers both without buying two separate kits.