Ballistics, reloading, and forming wildcat cartridges are a hobby of mine too. I have over 35 years experience with reloading; so I know how a typical bullet perform and what powder to use with any given caliber. Back in the late '60's I was the first person in my area to own a .17 caliber rifle, a .17 Ackley Bee built on a Martini action. Later I had built several other rifles like a .257 Ackley Improved, .22 K-Hornet, .25 Souper, .17/223, 6.5 X 257 Roberts, and one, I still own, a .458 X 2" AMERICAN built on an Old Remington M-722 Action. I don't really care for these "Short Fat" new cartridges they are currently placing on the market.