Hodgdon, Speer, Lee, Hornady all list the 32ACP bullet as .312", Lyman lists .309".
I'm thinking the factory loads use a .311 bullet.
SAAMI says(groove diameter) .311 for the .32ACP .312 for the .32H&R, and .312 for the .32 S&W short and long.
BUT, the SAAMI specs for bullet diameters are .3125 for the .32ACP .312 for the .32H&R mag,
and .315 for the .32S&W short and long.
Nevertheless, I use .311 .32 cast bullets in the .32ACP and the .32 S&W's, and I'll be using them in the .32H&R mag too.
And I'll be using .311 jacketed bullets in the .32 H&R mag as soon as I turn up a few inserts chambered for it.
I've found it's less work to just make light cast bullet loads for plinking. I run a .32 round ball through a .309" sizer
and get a small elliptical bullet for my efforts. I shoot these with 4 grains of Red Dot out of my various .30 cal rifles.
They go pop and shoot to the point of aim. Don't even need ear plugs with these...
Yeah, subloads are a blast