Paul and jbmi pretty well summed it up.

I have several 30-30's, a 32 special and a couple 35's. I bought a .32 special just because I wanted one but there is so little difference between it and the 30-30...and exactly why it faded away. The 35 Remington is a fine round and really a logical step up from the 30-30 for lever rifles.

There have been wildcats of every flavor developed on every case and for what realistic value is hard to justify. if you want do so 'just because' then go ahead, sure will be different. I have owned rifles in 22-250 Ackley and .280 Ackley and I like the Improved designs but they are not worth the trouble IMHO. When it comes time to sell of your pet projects they move on the gun market like a constipated sloth. PO Ackley said in his later years that the AI designs were not worth the trouble after improved propellents had been introduced to the market. I agree. The 338-30 is not a AI design, I know, and I apologize for digressing from the poriginal question so far. But, as has been said, suitable bullets for a tube magazine gun do not exist and if you plan on using a hand cannon like a Contender, the 35 remington is readily available and is a dandy.

Don't see where it would be a whole lot different than a 32 WIn. Special.