You can find a set of dies or a sizer here. I do not believe there is a case that can be easily formed for a 28-30.  Post on this site "possible;
              Huntington's sells [or did] 6 x 70R brass that can easily be sized for the 28/30 Stevens, it is very nice brass made by Norma.  Don't look for 6 x 70R brass in your cartridge books, it ain't there.   ledball " 

Bertram made brass for 28-30
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Kurt

I guess my real question is why would someone make forming dies for a cartridge when there is no other brass available from which to form a cartridge?

I have been shooting a .28-30 Stevens since 1967.  I started out with 40 original UMC cases.  Over the years I have lost 4 of those because the primer pockets got too loose.   

Maybe 8 years ago, I bought 2 boxes of Bertram.  They were too big to go into the chamber, so I ran one in a C&H FL die.  It promptly split.  I annealed the surviving 39.  I used the brick in a bucket of water method, heating with a propane torch.  When the case turned color, i knocked it off the brick & into the water.  Dried & lubed the cases. Then sized them.  Lost 3 more, but the remaining 36 have been shot dozens of times.  But I always breech-seat and never do more than decap & recap.  The Bertram cases are not pretty & the headstamps are ghastly, but they work.  If I were desperate, I would buy a couple of boxes and expect 10 % + failures on forming, after I annealed them.

I also have 40 RMC cases, made by the previous management.  They are OK, but the primer vents are tiny.  Decapping is a nuisance, so I don't use them much.

I have a nose-pour Hoch mould, 142 grains.  Mankind can go no further.  Pistol primers, 11.7 grains of SR4759 and a cork wad in the case mouth.  Seat the bullet with a plugged case.  I have a couple of Lyman moulds for the old bullets, but the Hoch mould is so much better that the Lymans are just collector pieces.

The 28-30 is my favorite cartridge (other than the 22 LR).  I have a second 28-30 in the works, but it has been in the shop for so long that I will probably be D&G by the time it is shootable.  My grandson will get it.