–Security Guard, shooting at Lucy, and first stating what may as well be an in-series meme concerning most firearms
This is a listing of the various firearms seen in use in the anime version of the Elfen Lied series. For the most part, the firearms seen in the manga version are much harder to determine with any real accuracy. While they may in fact be identical to those shown in the anime and are certainly the same type, a true determination is impossible. A separate listing below will speak broadly of these.
Weapons are listed here by order of appearance in the episode: images shown are merely the best visual representation in-series and do not necessarily follow this order.
Admin's Note : Any and all debate over the nature of firearms, for or against, is flatly forbidden here. The issue is far too contentious, and in any event can not be settled here. These weapons are a part of the Elfen Lied universe, and most who use them in it have reasons for using them, in situations and with outlooks that render any such debate totally moot.
The sidearm for police officers and S.A.T. forces, most noticeable scene is when Bando, while shipping out to locate "Lucy", threatens one of his squad mates with a stainless steel SIG-Sauer P226. Police officers apprehending Lucy when she was a child are armed with the P226 as well.
Professor Kakuzawa uses a FAMAS G2 in episode 10 to kill the escaped Number 3, stating that while the Diclonius' vectors can block normal bullets such as the MP5 9mm rounds, it can't stop an armor-piercing round such as the 5.56 so easily.
Chapters 64, 65, 66, 67, and 70 - Soldiers, possibly police, armed with assault rifles, fighting Mariko and being killed by Lucy
Chapter 64 - Harpoon missle that was originally developed as an anti-ship missle in the 60's but later SLAM (Standoff Land Attack Missile) was further developed directly based on the harpoon missle in the 90's.