Where to buy magpul rails or equivelant?

[Moser40s&w]

Lookin to buy done rails for my mdt Tac 21 build and figured rails were better suited for the black and green rifle section. I need the L7 and L11 lengths. None of the vendors seem to have anything does anyone know where to find some rails by magpul or another companies with the same spacing for mounting

Thanks Logan