Mounting a light, sling, bipod or grip starts with understanding your rifle's rail interface. The two systems you'll meet most are M-LOK and Picatinny — here's how they differ and how to mount accessories with confidence.
Picatinny (1913): the universal standard
The Picatinny rail (MIL-STD-1913) is a continuous row of raised slots that accessories clamp directly onto. It's the long-standing universal mount — almost any optic, sight, grip or light with a Picatinny clamp will fit. The trade-off is weight and bulk: a full rail is heavier, and the sharp edges can be uncomfortable without rail covers.
M-LOK: the modern, slimmer system
Developed by Magpul, M-LOK uses a series of slots cut directly into a lightweight handguard. Accessories (or M-LOK adapters) bolt on with a T-nut that locks into the slot — secure, repeatable and far slimmer than a quad rail. It's now the dominant standard on modern handguards. Mount lights, sling points and bipods directly to M-LOK, or add a short M-LOK Picatinny rail section for optics that need it.
What about KeyMod?
You may still see KeyMod, an earlier slotted system. It largely lost out to M-LOK and is now uncommon — if you're building fresh, M-LOK is the safer long-term choice.
Mounting the essentials
- Bipods: mount directly to M-LOK (Magpul M-LOK Bipod), to a Picatinny rail (1913 Bipod), or to a sling stud on hunting rifles.
- Slings: add a QD socket with an M-LOK QD mount or a Picatinny RSA, then run a QD sling.
- Lights & accessories: use the matching M-LOK or Picatinny mount for your device.
Our recommendations
For most modern builds, M-LOK keeps things light and clean. Browse M-LOK Accessories, Bipods & Mounts and Slings & Sling Mounts to kit out your rail.