Off the shelf goodness for you Maryland clone guys! I thought I would share this since this build specifically states that it comes with a heavy barrel.
https://danieldefense.com/m4a1-sopmod-block-ii-clone.html?utm_campaign=M4A1_SOPMOD__Clone_II&utm_content=touchpoint_1_general_july_template&utm_medium=email&utm_source=zaius
https://danieldefense.com/m4a1-sopmod-block-ii-clone.html?utm_campaign=M4A1_SOPMOD__Clone_II&utm_content=touchpoint_1_general_july_template&utm_medium=email&utm_source=zaius