The .950 JDJ is the world’s largest sporting round. It is so big the US Army does not consider it a small arms weapon, they limit those to .50 cal and under. This gun is basically shoulder-fired artillery.
The round was developed by Manufactured by SSK Industries, and gets its name from the president of the company J.D. Jones. The company had to get a sporting exception from the ATF to even make it legal.
SSK Industries manufactured only three of these rifles, and as of 2014 SSK no long produced ammunition for it. When thy were producing ammo each round cost approximately $40. The gun itself is estimated to be worth between $25-30,000.
So if you have a T-Rex hunt scheduled this just might be the gun for you, other wise I have no Idea what you would use it for. It serves no practical purpose besides making a big boom.