I use my magpul foregrip as a handstop while gripping the bottom of my quadrail. I also use it as a stop for the bag/cushion while sitting down. All Hera Arms AR15s come with free floating quad rail. You can order the rail in the states, but it will cost about 250 dollars. It is top notch German quality, so it is worth it. Type in Hera Arms on youtube and a company explains the Hera Arms parts and how to order from them.
Also go to Hera-arms.com.