From Halo Costuming Wiki

[edit] Weapons Hub Entry

Halo 3 Shotgun

Also referred to as the "M90A Close Assault Weapon System".

According to information found on Halopedia, this two-handed weapon's length is 123.9 cm (48.8 in.) long, and it weighs 5.4 kg (11.9 lbs) when empty and 5.7 kg (12.6 lbs) when loaded.

Further Storyline information is availible here: Halopedia Information Page (external link)

[edit] Links

See how members of the 405th Forums approached the creation of their own Shotguns, on their own WIP's (still needed), and how some of them looked when completed, when they were shown off (still needed).

Blueprints are availible on the 405th Forums: [Wizard of Flight's Blueprints].

Pep files (.pdo's) may be availible: Pepakura_File_Index#UNSC

[edit] Downloads

A Reference Pack is availible (hosted by vrogy): [Shotgun Reference Pack]

A Picture_Pack is still needed for this item.

To my knowledge, no 3d models (other than pep) are currently available for this item. If you are aware of any, please add a link to them from this page.