To install the A91 move the files into your WAW raw folder.

If it asks you to replace any files do not!

Once done that call in your mod.csv:

weapon,sp/zombie_a91
weapon,sp/zombie_a91_upgraded

And move the images into your mods folder.

The weapon file may need some edits as its pulled right out of my map town of the dead.

Credits to this mod go to:
Cowman (Custom anims)
Nikolai (Idea)
Jzob (Model)

There are no sounds in the zip you will have to used your own sounds or find your own.