Up from the grave it arose! Ha!
Love the six rnd 32 L. So much that since I do not reload I tried Buffalo Bore offering of 32 auto +P.
.32 ACP +P Ammo 0.312 - 75 gr. Hardcast F.N. (1150fps/ M.E. 220 ft. lbs.)
Yes, it is pricy though I added a 20 rnd box to some .22 short hp I ordered from Midway. I informally tested this against Sellier & Bellot Ammunition 32 S&W Long 100 Grain Lead Round Nose[actually is barely flat tipped though not nearly as wide as a flat tip, perhaps the width of a BB] Muzzle Velocity: 886 fps Muzzle Energy: 174 ft. lbs.

I used a fairly solid though aged 2x8 in front of a well seasoned slab of oak w/inch or two air gap. The LRN stopped roughly an inch into the oak slab. The 32 ACP penetrated about the same except the base of it finished in front of the tip[of the 100gn LRN], since flattened to resemble a wadcutter, of the 32L.

One argument is blow-by due to one or possibly two thousands difference in the 32 L Vs. 32 acp. Perhaps, but I'm not shooting boxes through the model 31 at $1.15 a rnd[not including shipping]. The S&B is 49 centavos a pop.

There's a noticeable pistola flip w/100gn. There's none w/75gn. So, perhaps there is blow-by, yet I only use the high priced hard cast for carry. Yet another reason, after burning through some Magtech 32 long LRN, for not cleaning the lead out of the 3" brl. YMMV.

However, I like the hotter 75 gn flat hard cast penetrating deeper w/help of an extra 46 flbs of MV. As well I experience no split cases or issues using the star extractor.

I have BP 32 that I would not shoot the most anemic modern powder load through on a bet. I absolutely do not encourage any hot loads in older top latch or BP designed firearms.

This hot .32 ACP in me modern I frame manufactured in the 1950s will penetrate being just shy of 1.5X diameter of a .22 LR and almost twice the weight of a traditional 40 gn LR boolit.

Now, if I had me druthers I'd be hard pressed to pick twixt the .32 ACP 75gn flat hardcast out of the 3" brl or the 27gn .22 SHP out of a rifle brl.

In fact they compliment each other w/73 flb .22 SHP designed for maximum expansion quickly on a soft target and the 32 ACP hardcast designed to retain weight and penetrate against thicker/denim/leather covered target.

OT, but I highly recommend the .22 shp for dispensing tree rats out from under feeders.

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Caveat venditor.