It used to be, and still is a very effective wildcat cartridge. In the last few years they have legitimitized it by offering factory ammo for it, and even rifles thus chambered. The cases can be easily formed by running through sizing die without any other steps. Be SURE to use proper amount of evenly applied case lube when forming. Naturally it's better to get factory .338/06 cases than to form them as they will last a little longer if you're not good at annealing. Are you wanting load data? Personally, I always liked the .35 Whelen better in the past because of the availability/wider variety of .35 bullets over .338 bullets. The reason is in the past, the only bullets available were intended for .338 Win mag velocity and didn't expand as good fired from lower velocity. This has all changed with great bullet design of late, and bullets intended for the "new" .338 Federal, which is nothing more than making another wildcat legitimate. If you need more let me know and I hope I was of at least a small help.