I was thinking about sending a barrel into SSK, they will do a 222 JDJ mag rechamber for 75.00 + plus another 75.00 for a custom set for reloading dies. Was just wondering how much different there is bewteen this and a 222 magAI. I would't think there would be very much.
You are still confusing terms pard. "JDJ" is a J.D. Jones thing and originally developed for TC's... "AI" is a P.O. Ackley thing developed for mostly bolt rifles - two completely different proprietary classifications from two different wildcat developers. Anybody can chamber the AI's, but not the JDJ's without JD's permission. Being rechambered by JD does not make it a JDJ just because he rechambered it.
To be called a 222 "improved" anything, it would be based on the 222 Rem or 222 Rem Mag cases, which are both rimless cases. Even if JD does rechamber your barrel to a 222 "improved" something, it would not be called a 222JDJ something. It could be called a 222 I/AI or 222 MAG I/AI or similar though.
The .224 caliber "JDJ" improved is based on the 225 Win case, which is a rimmed case. It is stronger than either of the 222 Rem cases and has the rim most thought worked better in the break action firearms back when they were developed. IOW, most wildcat/improved cases developed specifically for the TC's were made from rimmed cases (not rimless). Best known for developing them in the old days are JD Jones and Don Bower (the 22 Super Bower, Don's .224 improved, was based on the 307 or 356 Win cases).