Charlie, thanks for your interest in Riflespeed. The most certain way to determine fitment is to use the Configurator found on the "Choose your Gas Control" page here: https://www.riflespeed.com/Choose-your-Gas-Control_ep_41.html. We also have several YouTube videos that can help on our YouTube channel. The most common issue that prevents fitment is handguard length. You can enter different measurements into the handguard field to see what would work.