What are you trying to mount? Your answer to this question is crucial in order for us to help you. Magpul sells mlok rail sections. They are probably no more than 2-3" long. There may be some aftermarket ones that are longer but you'll have to use your Google fu for that. The idea behind the mlok handguard is to only have rail sections where you need them and not a continuous rail. If you want that then you should find a gen 1 with quad rail or trade someone here on the site. If you are adding accessories, see if there are mlok versions that mount directly to the rail. Magpul makes a slew of gadgets that do.