Key the Metal Idol is an experimental OVA series from Studio Pierrot released from 1994 to 1997. The first 13 episodes are each 25 minutes in length, while episodes 14 and 15 are 90 minutes each.
The following weapons were used in the OVA Key the Metal Idol:
A dead soldier is seen with a Carl Gustav recoilless rifle during the aftermath of the PPOR "test". The image appears to be flipped, although whether this is a mistake or intentional is unknown.
Sergei (also referred to by the codename "D") uses a fictional handgun during the earlier episodes of the OVA. This elaborate weapon appears to be based on a Colt M1911, although it is difficult to tell if it is an original design or just heavily customized. The weapon boasts a myriad of features, including an extended barrel, what appears to be either a folding stock or a rearward weight, extended magazines, ergonomic grips, an extended barrel and guide rod, and a LED indicator that changes based on what kind of ammunition is loaded.
The security guards at Ajo Heavy Industries are seen using ARWEN 37 riot guns during episode 14. Surprisingly, the weapons are depicted as firing tear gas grenades, as opposed to the (incorrect) explosive grenades that usually coincide with it's depiction.
