I saw a TV ad for the “Lone Survivor” movie in which the Seals were carrying some hefty looking guns. Are these some Hollywood creation, or are they copies of something our military really uses? If so, what are they?
You’ll probably find useful the IMFDB page for Lone Survivor. Lone Survivor - Internet Movie Firearms Database - Guns in Movies, TV and Video Games. Basically, it’s a bunch of modified M4’s with suppressors. This jibes with what Ed Darack wrote they carried (SOPMOD M4s with ACOG sights and lasers) Operation Red Wings, Operation Whalers, and the book VICTORY POINT in which they are comprehensively documented / Ed Darack. The movie has some of them carrying Mk. 12 SPR. Strange that they weren’t using 7.62, but whatever.
You’re probably looking at the M4A1 carbine with the M203A1 grenade launcher.