This here is a life-size model of a big ol' sniper rifle from Halo, made entirely out of Lego bricks by Nick Jensen. It's very, very impressive, even if it won't do much to protect you from the Covenant.
Clocking in at 63 inches long and over ten pounds in weight, this thing features a removable magazine, moving safety and sliding bolt. It has a sweet-looking scope, and is really just insanely detailed. And with good reason! It apparently took poor Nick over four months to complete the thing.