Brass is available, and looking at a case right now, and it looks to be a great little parent case for wildcatting! The H&K 4.6x30 looks to be another good little case, and already almost a .17 caliber, but cases are not as readily available for now. But holding the two cases next to each other looks to be great prospects!

HHI 812,

I don't foresee a great demand for the wildcatting of the 5.7x28.There would be too much alteration required on the availible firearms to feed and extract this case.
The.22Hornet is practially the same base diameter as the 5.7x28.It is more practical,due to availibility and the fact that it is rimmed,
making it a better option for singleshots.There are also bolt guns availible that are manufactured
to feed and extract the Hornet case.
The only practical use I could see for a wildcat
on the 5.7x28 case might be a 5mm Rem.converted to centerfire or in a semi auto pistol.Many wildcats are built for personal vanity or research,so only you can decide if it is worth the time and money to you.

WC

Two companies, Schroeder and Certech, already produce centerfire 5mm Rem Mag cases for those shooting rifles converted to the 5mm Rem Mag, so that reduces the need for a 5.7mm wildcat even more. That would probably be just as potent as any 5.7mm wildcat, as some on Saubier.com have been getting 2400-2500 fps from it (referred to as the 5mm Craig) with 30-33 gr bullets.

Wildcat Crazy & Geo

Thanks guys.....More for me.

HHI 812
I posted to you in another forum.
The 25ACP shell holder works for these...it's tight, but it works.