Have funny idea.
I just procured a 32 short RF low wall with a good bore.
Planning on rechamber and convert to CF, have been wanting to make a 32 ideal short except .312, usually I'm after another 32 s&w long but since a low wall I could get more juice from it.

Then I had the thought, what if I breach seated either smokeless or BP, to increase capacity to that of a real 32 ideal case.

I have a 32 h&r mag reamer that I use for s&w chambers. 
The other thought is a 327 fed mag case used same way for maximum capacity.
Just some wild thoughts. 

Unsure of how breach seat throats are designed and different from a normal throat.

Any feedback would be appreciated. 
Mike

From past experience with using the 32 mag case (25 Schuetzen), I would go with the 327 case its suppose to be much stronger. I have no opinion on your idea otherwise, good luck.

There are two different types of reamers for the 32 H&R magnum: a pistol reamer, and a rifle reamer.  The throats are different.  The pistol reamer is for cutting chambers in a cylinder, and the rifle reamer is for use in a barrel.  Brownell's sells pistol caliber chambering reamers for rifles. (I think they're made by Manson, but can't remember right now)  If you use a pistol reamer for chambering a rifle, you might not get the accuracy that your looking for.  You could use a throating reamer as was suggested, but the pistol reamer on it's own may or may not give the best results.