Kind of ironic considering both KeyMod (by BCM) and MLOK (by Magpul) originated in the civilian market. The us military choose Mlok and the civilian gun market follows the military unless there's a substantial reason not to, so with how close KeyMod and mloc are I expect within a decade KeyMod accessories will completely disappear. Alternatively called a 1913 rail or a Picatinny rail named after the Picatinny Arsenal where it was developed the new standard swept the industry. On the other hand, if you want to use weight as a determining factor, KeyMod is lighter than Mlok (though just barely.kind of like how mloc is stronger, though just barely). M-Lok-compatible accessories, like this Magpul Angled Fore Grip, feature screws with a T-nut that lock into the M-Lok slots. Yes, I read the official tests that concluded mlok was better than KeyMod, but that test focused on how hard it was to knock off accessories, was fairly unscientific, and the difference in the test results between the mlok and keymod was basically a rounding error, with Picatinny beating both by a significant margin (which is probably why we see really expensive stuff like optics always on Picatinny) Compatible accessories can be mounted to a bracket that locks into those openings. In other words, M-Lok and KeyMod both have integrated openings machined directly into the hand guard. The bolts that tighten the mounting nuts of a KeyMod accessory do not protrude through the rail as physically far as the bolts that tighten the T-nuts of an M-LOK accessory, so a KeyMod rail can fit snugger and be closer to the barrel of a firearm. The difference between Mlok and keymod is tiny. Both the KeyMod and M-Lok systems support direct attachment of optics, lasers, flashlights, bipods, and other accessories to a negative space mounting point. KeyMod Accessories Don’t Protrude as far into the Rail as M-LOK Accessories.
![keymod accessories on m lok keymod accessories on m lok](https://ae01.alicdn.com/kf/HLB1JbnbL3HqK1RjSZFkq6x.WFXaY/AR15-Aluminum-Black-KeyMod-Rail-Attachment-Mount-Adapter-With-QD-Sling-Swivel-Compatible-M-lok-For.jpg)
![keymod accessories on m lok keymod accessories on m lok](https://ae01.alicdn.com/kf/HTB1h7.MXhrvK1RjSszeq6yObFXa5/Gun-Accessories-Keymod-M-LOK-Handstop-Kit-Angeled-Foregrip-Accessories-with-Guide-Rail-Tactical-Handguard-for.jpg)
Ally guns (real and airsoft) use Picatinny. I prefer Picatinny for the better retention and flexibility in where accessories are placed.