I've reloaded for the .32 ACP for over thirty years. The limiting factor in accuracy of small handguns is short sight radius. A personal defense gun will most likely to be used from near-contact distance to no more than 20 feet. Sight radius is less important because the recommended technique in close quarters situations is "target focussed" maintaining situational awareness, watching the bad guy's hands, moving to cover, etc., rather than being "sight focussed," as is necessary when engaging the sitting grouse or rabbit 20 to 50 feet away that you want to eat.
My favorite cast bullet handloads in .32 ACP use either the 98-grain Saeco #325 semi-wadcutter. If you dont cast your own, buy the 94-gr. .312 flatnose Cowboy bullets from meister and they work fine. I cast bullets of wheelweights, tumble-lubricate them in Lee Liquid Alox, and load them as-cast and unsized with 1.7 to 1.8 grains of Bullseye. The Saeco #325 can be crimped in the normal revolver crimp groove. Do not load the Meister bullets shorter than 0.95 inch overall. Because of the flat nose profile, do not exceed 0.975 overall length to prevent bullet noses from dragging against the front of the magazine box.
I taper crimp using a custom Lee Factory Crimp Die. This has a carbide full length sizer which removes any bulges caused by mis-match of the bullet diameter with the internal case wall taper, ensuring easy chambering and sizing the bullet, if needed by compression inside the case. A custom Lee FCD costs $30. I highly recommend one for anyone who is serious about reloading for the .32 ACP.
Alot of misunderstanding is caused by inaccurate mythology and folklore in old Lyman manuals which recommends sizing cast bullets to the groove diameter of the barrel. This results in undersized bullets not fitting the forcing cone or throat and being gas-cut, causing leading at the origin of rifling and poor grouping. Recommended practice for assembly of lead bullet ammunition in the firearms industry is that bullets be of diameter to enter the barrel forcing cone without resistance, but to fit as closely so that the bullet upsets instantly upon discarge form a positive gas seal, prevent gas curtting.
Excessively hard, undersized commercial cast bullets are more likely to cause leading than softer ones of correct diameter. The ideal condition is for bullet alloy hardness to be matched to working chamber pressure, and for the bullet to be not smaller than 0.0005 inch l;ess than chamber throat size. Maximum suitable chamber pressure for a given caast bullet hardness is estiminated by multiplying the Brinnel Hardness Number times the constant 1440. For instance wheelweight alloy when slowly air cooled after casting has an average BHN of 12, so to estimate a correct working chamber pressure 12x(1440) = 17,280 psi. This is a good match for standard .38 Special or .32 ACP ammunition which has a maximum average chamber pressure of about 16,000 psi.
Typical wartime European pistols vary all over the map with respect to barrel bore and groove dimensions, twist rate and chamber dimensions. Colts, Berettas and Walthers have 16 inch twist, FNs, CZs and Mausers have 10 inch twists. FN, Mauser and Walther pistols in my collection have groove diameters from .307-.309, Berettas, CZs and Colts run from .310-.312. I have not seen chamber throats in any .32 ACP pistol smaller than .311, but I have seen WWI and WWII era Spanish, French and and Italian pistols as with throats as large as .316. This wide variation in bore sizes coupled with factory jacketed bullet diameters which vary in differ ent makes of ammunition and component bullets from .308 to .312 explains most of the accuracy problems people experience with the .32 ACP.
In my experience European Sellier & Bellot, Sako, Lapua, and RWS ammo having the smaller bullet diameter works best in Walthers, Mausers, MABs and FNs, while larger Privi-Partisan, Fiocchi and handload using Magtech, Remington Hornady and Speer jacketed bullets are more accurate in Kel Tec, Beretta, Colt, Astra, Unique, Star, Llama and CZ.
My 1935 Beretta wartime pistol had an oversized .315 throat with .313 groove diameter barrel and produced six inch-plus groups at 25 yards with its original WWII salt and pepper barrel. After fitting a new barrel custom machined from a 14 inch twist Hart .308 blank with minimum CIP chamber body and .312 forcing cone diameter set up to headspace on the case mouth, groups shrunk to 3 inches at 25 yards with good handloads, using iron sights. A custom Beretta target pistol with 6 inch Douglas barrel and 4X Leupolkd scope shot the amo ammo into an inch at 25 yards.
Do not shoot huge quantities of cast bullet loads with bullets heavier than 90 grains in mouse guns having alloy frames, because they are harder on the gun and they may develop cracks.
In my chronograph testing Remington, Winchester, Federal and Magtech 71-gr. FMJ ammo average only about 850 f.p.s. when fired from a "full sized" .32 pistol such as the Walther PP, Beretta M70 or FN M1922. CIP specificiation 73-gr. ammo such as RWS, Geco, Fiocchi or Sellier & Bellot does 900-950 f.p.s. TypicalUS make 60-gr. JHPs typically are about 900 f.p.s. but because of their lighter bullets, do not provide enough recoil impulse to reliably cycle the older European pistols.
The heavy bullet loads discussed here approximate the velocity of .32 S&W Long ammo fired from a 4-inch revolver, with a recoil impulse which is similar to European 73-74-gr. hardball ammo. My WWII-era pistols don't function at all well with typical US 71-gr. commercial ammo or the popular 60-grain JHPs, but these cast bullet loads are accurate, are great for recreational shooting or small game and run the wartime guns like a pony trotting .
Enjoy!
Scott
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