There are a number of custom mouldmakers today that can produce virtually any mould one could imagine, and with custom dimensions, probably for under $200.00. However, the buyer would have to know key dimensions of his bore and chamber. I have not looked up the bore twist rate for a .348, but it's all a lot more complicated than designing a "light" bullet. If the bore twist is not compatible with a bullet's length and weight, it will shoot poorly, maybe very poorly. If a cast bullet has an undersize diameter, even if only slightly undersize, it will shoot poorly and lead the bore. If it's oversize by very much, again, all sorts of problems.

Recoil is a subjective thing and affects everyone differently. I wouldn't think recoil from a 250-grain factory .348 load would be excessive for most persons, except possibly from a benchrest, and that, only after firing many rounds.

No need to further address the difficulty in obtaining brass or loaded ammo; that's been adequately covered.

This whole matter is really not a project for a beginner and/or non-handloader.