To keep it brief, I saw the M&P 15 pistol and I really like the way it looks BUT I want to build one, not buy one. The issue I'm having is, I have no idea what length the handguard is and would like someone with more experience to help me out. Their website says a 7.5" barrel and I THINK the handguard will be an 8" to have the muzzle device sticking partway out. But might be a 7.5? I know I'm asking about a pistol, however it's an AR type, so I felt like posting in semi-auto rifles might get better results. Same idea could easily apply to a rifle as well. Picture for reference.