Originally Posted by cyphertext

The M-LOK refers to the system to attach devices to the handguard. If your optic is attached via the rail that is part of the forged upper, that is not M-LOK. That is standard picatinny.

The S&W site states that the your rifle comes with "2” M-LOK® Picatinny-Style RailPanel Included".... that refers to a piece of rail that you can attach to the handguard via the M-LOK system to use items that would typically attach to a picatinny rail. It is an adapter, M-LOK to Picatinny.

The rail your optic sits on is not M-LOK. It is longer than 2", so obviously not the rail piece stated above. It is the same picatinny rail that is on my Sport, or any other M&P 15 railed upper receiver.

So, just to be clear, you have a standard picatinny rail that is part of the forged upper receiver where you mount your optic. You also have a Magpul M-LOK carbine length handguard, where you can attach things such as lights, bipods, sling loops, or other accessories using the M-LOK system, or you can utilize the 2" adapter rail to attach accessories that are picatinny to your handguard.

Not trying to argue, just trying to let you know the difference so you know what you have.