I have seen several lists of calibers available for the KP1, some more extensive than others. This is the most inclusive list I could find, and it comes from the Knight website. Calibers include...
"In addition to .50 caliber muzzleloader, barrel calibers include: .17 HMR, .22 LR, .204 Ruger, 22-250, .223 Rem., .243 Win., .270 Win., .308, .30-06, .300 Win. Mag., and 45-70. Shotgun barrels include 12-gauge smoothbore, 12-gauge muzzleloader, 12-gauge 3-inch rifled slug and 20-gauge 3-inch rifled slug."
I was encouraged as this list is longer than in my KP1 manual that came with my 45-70 and longer than their KP1 pdf catalog available on the Knight website.
Here is the link I found...
http://www.knightrifles.com/PressRoom/Releases/KP1_Transforms_the_Legend.htmI have sent them an e-mail asking about calibers, and of course left them my list of suggested additions. If you are a regular reader on the Handi-rifle forum, the new caliber wish list is huge but largely unrealized. It cant hurt to ask though. My caliber choices were a little off beat. I want a 44 mag (20 inch barrel) and a 6.8 SPC (I know this is a long shot), a 500 mag, 260 Rem or 7mm-08. I would not buy them all to be sure, but one or 2 would find there way home with me eventually.
Cheers, xhare