I just mic-ed a selection of new GA Arms 100gr .32 H&R Magnums and found a maximum OD at .25" past the rim of .334" (Actually, since they are straight walled, that could be measured anywhere!). I also mic-ed a selection of new Fiocchi and Russian Nagant ammo to find a minimum OD, again, at ~.25" from the rim, of .352". That means, with a tight cylinder bore, the .32 H&R cases will 'grow' by .018" in OD - beyond useful reloading/re-sizing capability. The H&RM cases are tougher than the S&WL cases, especially those MagTech's I shot, so they likely won't split.
Another interesting problem - the .32 cases droop at the rim, placing the bullet 'off-axis', thus the spitting at the 'closed' b/c gap. That can also happen to a lesser extent with .32-20 brass resized with an M1 Carbine carbide sizer, as it measures .3485" at the same .25" mark below the rim. While it's even heavier brass will 'grow' slightly (Still easily resized.), the rims, if they fit at all initially, were canted slightly by bearing against the inner raised edge of the cylinder. I remedied that in mine by turning .024" off the rims with a Taig micro-lathe - a bit tedious for the 300 cases I did, but worth it for decent ammo. Of course, thinning the breechblock will prevent the need for rim thickness adjustment, as would turning that inner rim down slightly. I prefer to leave my Nagants stock, altering the ammo to fit.
Others may use the straight walled ammo at their own risk, but I am not that way. The few rounds of GA Arms ammo I did shoot made me want a proper .32 H&R Magnum revolver, of course!
Stainz
PS The spitting with Magtech .32 S&WL ammo left lead residue on the outside, ie, convex, side of the barrel's inverted forcing cone. This became copperish in color after a few .32 H&RM's, explaining what was zinging pass my hands. It has dark powder residue after my homebrews - much less after the 'proper' (Ruskie or Fiocchi) ammo, as expected due to their longer cases bridging that tightened b/c gap.