I just had to share this link. These are photos and a video of SSK Industries .905 caliber bolt gun.
http://www.theblaze.com/stories/want-to-see-the-worlds-biggest-caliber-rifle-in-action/
Jym
http://www.theblaze.com/stories/want-to-see-the-worlds-biggest-caliber-rifle-in-action/
Jym