I'm doing .314. Works well in the Marlin, and is a bit tight in the Ruger Single SIx, although very accurate. I've followed alot of Ken Waters suggestions, and found the 4.5gr. of 800X works like a charm.
The bullets I'm using are actually 120gr. They are bigger than most would have considered. They look very similar to the Oregon Trail 120gr. (or so) offering for the 32-20. After shooting the little 85gr., I prefer these for 2 Bobcats, and the several ***** I got this Winter. I can drive this bullet up to about 1450fps with Lil Gun very accurately as well. The lack of a gas check is what is keeping the speed down.
Hornady LSWCs measure .314" and shoot very well in my 1894CB and my S&W 631. But they don't feed for beans in the 1894! I bought a box of 500 MEISTER LRNFP 94grs .312" at the local Sportsman's Warehouse and they feed great but shoot all over the paper. I measured them and they go .3107-.3114". I found they work well as a small game load in my 336CB in .30-30 with Trail Boss powder. I found .312" Hornady and Sierra jacketed bullets shoot and feed well. I even shot some .308 Speer "Plinkers" and they shoot well enough for close-range rabbit shooting but they don't feed well. I can't seem to get any kind of jacketed bullet to shoot well with Trail Boss powder. The extreme spreads and standard deviations run way too high. I guess they are right when they say it is for LEAD bullet loads. It is the best I've found for duplicating BP loads; plus it fills the case almost like black powder. However, it does not like any form of compression whatsoever; not even letting the bullet base touch the powder when seating!
My Marlin also measures .312" I assume the throat is large as I get best accuracy from .314" bullets
My Ruger Bisley needs a .313" bullet, the same for our S&W's.
The Marlin seems to prefer lead bullets 100 grains and over. The 115 grain Lyman 311008 seems to be my most useful mold. I have two 100 grain SWC molds, one with GC and the other plain base. These bullets shoot well but the plain base NEI SWC does not feed as smoothly as the "round flat" profile of the 311008. The GC check Lyman 313631 feeds well.
Varying amounts of 800X seem to work well in every .32 Magnum I have tried it in.
In the heavy frame handguns 10.0 grains of Hodgdon 110 behind 100 grain lead bullets is a very good maximum load.
In the lighter frame guns - J-Frame S&W - 9.5 grains is best. With the 90 grain Sierra JHC 9.8 grains of H 110 is a good maximum load in our handguns.
I am a small game hunter and the loads that seem most useful in the Marlin push the 100 and 115 grain bullets between 1300 and 1400 fps. This velocity range seems to give good accuracy, reasonable trajectory to 75 yards, and penetrate well while still alowing the bullet to retain a resonable amount of weight. I am shooting rather soft bullets of between 14 and 18 bhn.
I own an S&W modern K-32 in .32 H&R Mag, along a brace of Ruger Super Single-Sixes. I shoot .314 diameter cast bullets in all of them and they do quite well. Cast or swaged lead bullets should be the same size as, or a smidgin' larger than your revover's or rifle's throat(s) or poor accuracy will result and , more than likely, leading.
I have been using Desperado Cowboy Bullets' .32 RNFP at 96 grains. It is a soft alloy so should shoot well with low pressure loads such as those desired for cowboy shooting. It is light enough for revolver use. Being partially round-nosed with a flat point, it should work well in a lever-action rifle, too. Try www.cowboybullets.com and see. (No, I do not work for them)
Generally, shoot the largest bullet that will function properly in your firearms. In addition, with these soft lead bullet, get a custom inside expander that is only 0.001" smaller than the actual bullet diameter; e.g., use an inside expander of 0.313" for bullets sized 0.314", etc. If your inside expander is too small, it will allow the cases to be small and simply resize the bullets down as they are seated.