The short-necked 222 Rimmed AKA the 224 R-C Maxi can easily be made by using a 223 Rem reamer and running it in short, to the 222 headspace dimension. I used a 222 headspace gauge when making mine on a Martini Cadet and found that 357 Maximum brass would neck down in 2 steps with little trouble after being annealed. A light neck-turning was all that was necessary and resulted in a no-sweat tight-neck setup for presumably better accuracy; case length was correct right out of the box and needed only a light chamfer. I use cut-off 223 Rem dies to ensure resizing of the case base area to fit the somewhat reduced OD of the wildcat short-chamber base dimension. Standard 222 loading data works perfectly and in my rifle yields sub-MOA performance with no pressure or extraction issues. This Cadet has had its breech face bushed for a smaller firing pin nose as should all CF Cadets IMO.
I recommend this cartridge wholeheartedly as one of the least expensive and least-hassle wildcats to acquire (standard-size & commonly-available tools & components) and shoot (proven 222 Rem loading & accuracy data widely available) as well as one of the most useful of the smaller cartridges for actual field use up to 300 yds. It's
so little trouble that it's almost like it's not a wildcat at all, except for the headstamp and no factory ammo.
My friend Dave W has built a similar wildcat using a 223 AI reamer and dies, also on a Cadet, and here are some of his photos. The first photo is of the cartridge cases being formed, and even though he's making the Ackley Improved version you can get a good idea of how the unimproved case compares by looking at the partially-formed one, it's almost identical to the 222 shape.

Here's his rifle.

Here are 2 of mine, the takedown Greener on top is the short-necked 222 Rimmed and the Francotte on the bottom is a 219 Improved Zipper.

It's obvious I like these little rifles even though I may never actually
finish every little detail of either one. The Greener will get several other barrels, you can see their forearms in the photo, and I'm building a fitted takedown hard case for it. BTW the Greener's cheekpiece has aready been slightly reshaped, it looked way too long after I took the photo.
Regards, Joe