[swaghauler]

Osprey Publishing's The US Grenade Launchers, the M79, the M203, and the M320 by Gordon Rottman (ISBN: 978-1-4728-1952-9) is a pretty decent read. It does have some of the erroneous information that the US Army published in their field manuals before the 1987 edits of those manuals (triggering my questions about the M576 Multi-projectile round) but has LOTS of good info in it from the round types to the launcher's historical employment. It even covers a few rarer types of Grenade Launcher like the USMC's M32 6-round GL and the China Lake "pump action" grenade launcher. There is even a discussion of the equipment used to carry grenades in action (including "field-expedient" methods). I can recommend this book as well as Osprey's book on the RPG family.