I am going to build a schuetzen rifle on a Borchardt action which will be primarily for the bench.  I have narrowed it down to .32 RKS or traditional .32-40 of which I have dies for.  
I have done some searches here on this site and in the old SSRJournals but still have questions.
Do you shooters of the shorter cases see an advantage over the .32-40?  What pitfalls may I have with either case?
Do certain twists and bullet choices work better with the shorter case?
Will either case load easily in a Borchardt when breech seated?
What could you add that would possibly change my choice?  I'm sure I'll have more questions as I go with this.  Thanks.  Bob

Dave
Concerning rifling twist, if you could expand on your response I think it would be worthwhile to Old Win's questions. Are you getting better accuracy from 11.5:1 twist over the RKS gain twist with 11.5 at the muzzle? I am thinking of re-barreling one of my rifles with one of Ron's gain twist barrels.
Thanks

I have a CPA in .32-20 CPA, a Miller is .32 RKS, and two other rifles in .32-40.

The most accurate rifle is the .32-20 CPA but loading is a pain in the rear and case life is short.  It's not much fun to shoot.

I've never noticed any appreciable difference in accuracy between the .32 RKS Miller and the two other .32-40 rifles.  The .32- RKS requires a wad of some sort to prevent powder from spilling and has some case life issues as well.

The .32-40 case is easy to use and lasts (almost) forever.

So, unless your at the top of your game, dedicated to winning matches, and willing to tend to the care and feeding of the smaller cases, go for .32-40 and enjoy the shooting.

JackHughs

Frank:

My Borchardt in .32-40 requires me to also raise the breechblock slightly to have the case rim engage the extractor.  I keep a dental pick handy to pull the shell if I forget and seat the case in front of the extractor.

Pretty simple choice, Traditonal Schuetzen rifle use the 32/40.  Willing to live with something that looks modern use a short case wildcat.  Be a shame to mess up a Borchardt action making it into a modern rifle, personal opinion only.

Scores will depend on the shooter not the cartridge or rifle.

Boats

Both Frank and Jack have touched on two important points when using .357 based cartridges in rifles with high shoulders supporting the breech block. The first is getting the case into the chamber and the second is not slipping it past the extractor. With a little thought both are solvable problems. 
  The first rifle that I owned that took a small case was a Winchester that I had a chambered in 32 X .357 Dell, essentially that Miller Short. It shot well but was a pain to load. The case is so short that you couldn’t hold it and start it in the chamber. I had to lay it on top of the breechblock raise the block a little and then poke it in with a finger. It was a PITA and slowed down my load time. A similar architecture will make this true for the Borchardt also. 
  After some experimenting I went with a case that was the full length of the .357 Maximum case 1.600” long. Now I can hold the case and start it into the chamber on my Borchardt. The case inside is virtually a straight-sided chamber letting me place the wad anywhere along its length so essentially, internally, as the Miller short. The other issue is on the Borchardt you can slip a .357-based case past the extractor. This is overcome by after extracting the case raising the block just enough to snap the extractor back into its slot. It will stay there with out holding and you can load the next case. Do it enough and it will become habit and you will hardly know that you are doing it. 
  If I were going to choose a case again it would be a .32 Miller, Not the short, but the .357 Maximum on a straight taper case. It has all the advantages of the short case but you can hold it and load it in to the chamber.

40 Rod

Every mule owner I know, loves mules.   

   Joe.

Old Win 
Knowing what I know now I would have gone with the 32 Miller. They are the same length and the differences are minimal. I would bet that you could hold them in your hand and not be able to tell the difference. The 32 Miller is a known case so finding a reamer or having one made should not be a problem. 
  As far as the wad goes, I don’t think that you can get any of the shorter cases in a Borchardt without dumping powder. If not using a wad is the deciding factor, go with the 32-40.

40 Rod