I recently made a pack for use in FPS games. It contains a fully rigged arm and 7 weapons.
This is something I put together for my fellow blender heads.
It contains the fully rigged arm and two weapons.
The reason I chose these two is because I used and modified high poly models for them that I got from blendswap. Namely these two:
http://www.blendswap.com/blends/view/40982
http://www.blendswap.com/blends/view/17260

Thank you guys. Your models sped up my work with these two :)

The models have PBR textures as well, so you can put them in your game and they will look good. :) You will find them in the folder next to the .blend.
All models have BaseColor, Normal, Roughness, Metallic and Ambient Occlusion textures. The latter 3 is packed into one texture. Roughness in the Red channel, Metallic in the Green and AO in the Blue.

Let me know if you've used it in a finished product. I'd love to see it in action :)

If you like the pack and would like to get the full version, you can get it on CGTrader:
https://www.cgtrader.com/3d-models/various/various-models/fps-starter-pack

Thanks and have fun with it :)