The full length .357 Max case (1.605") is a straight wall case whereas the 32 Miller Long is made by trimming a .357 back to 1.470" so that you can taper it with a .223 die. Without the taper you may have a bit of a sticking problem.

Or were you considering using the .357 Mag case (1.590") and trimming it so you can taper it with the .223 die?

Most prefer the Maximum cases since they have thicker walls and last longer.

Just for grins, some time ago I took a few .357 Max cases and trimmed them to .357 Mag length, then weighed them and a selection of RP brass (trimmed to the same length) from different eras.  The difference in weights (volume) was insignificant...only about 5 gr. total spread, and the Max brass was not necessarily the heaviest.

David
Montezuma, IA

Keith,

    As you know, I have had a really good time with my Peregrine bench gun chambeed in Charlie Dell's version of the .32-on-a-pistol-case which he just called the ".32-357" and made first from .357 brass but later from the more exotic 5.6X50R Mag (rifle) brass.  I have used both and gotten equally good results with both, but not mixing them in a single string.  Charlie's reamer differed from the .32 Miller in that it was basically a straight taper from the rim to the case mouth, while the Miller has a short cylindrical section at the base.  What you may not recall is that I had Charlie's pet offhand rifle (also built on a Peregrine) for one season @ Etna Green while we were building my high-wall...so I can say with some experience that it is a fine caliber for both uses.  

    Brass for either is equally easy to make, and case loss rate is virtually nil.  The only cases I have lost (other than those actually dropped and lost   ) were a few Starline .357 mag cases that were GROSSLY overloaded when I first switched to H108.  

    My Peregrine's Douglas barrel really likes that Barnett bullet from moulds I got from you (thanks again!!   ) but with this case and chamber it is able to shoot a variety of bullets from 170 to 215 gr well on any given day.  This case is not weight sensitive at all, in my experience.

    The only downside to the short cases is that they are sometimes a little bit dicey to get into the chamber, but if you have a wad in place to hold the powder in, and if the side walls are configured properly (as those of that CPA certainly are) that problem disappears.  I think you will really like shooting it.  

See ya soon!
Froggie