M64 is a nice rifle,,a M94 rifle version as someone already stated since Winchester stopped selling M94 'rifles'.
I personally like the longed gentle curved pistol grip of the pre-war Winchesters,but certainly wouldn't kick a nice 64 aside if one came my way!
The 32Special is a nice cartridge, an 8mm by any measurement which if listed that way wouldn't bring any sales in the USA.
It was designed as a smokeless HV cartridge and came after the intro of the smokeless HV 30-30.
It was meant to take the place of the BP era 32-40 which was already being chambered in the M94. The 25-35WCF also was added to the 94's chamberings and was a smokeless HV offering from the beginning.
The 32-40 was a Marlin (Ballard) target cartridge. It shares the same bullet weight (165/170gr) with the 32Special and the same twist rate (1-16). With good reason, the bullet weight & dia at those velocitys stabilizes nicely in that twist range.
The 32 Remington (autoloader) is .320/321 dia, the near twin of the 32Spec ballisticaly and is 1-14" IIRC. Never intended to be a BP cartridge, it's from around 1905 or so (same as the 32Spec) and throws the same bullets around accurately.
Smokeless HV cartridges were on the market,,no looking back.
Certainly you can load 32Spec w/ BP and it'll be accurate. You can load 30-30 w/BP and it's very accurate,,try it. Plenty of Scheutzen shooters do it. 303 British was a BP cartridge originally too.
No secret science to it.
It wasn't Winchesters intent IMHO to look backwards at the start of the 20th century and the smokeless powder era to get people to start loading BP for their new HV smokless powder cartridges and designing them so.
Could they be loaded w/ BP,,certainly. Designed specificly for that duel purpose,,I doubt it.
I have a 94 TD Deluxe 1/2 oct rifle in 32Special made in 1913. It's quite a shooter. It was a good buy with it's reblued recv'r and bad re-stock. I've since restocked it(but not quite finished!).
It has the 'Smokeless Sight' on the rear which I understand was special for the 32Special. Not my favorite rear sight but special enough that it'll stay I guess,,at least for now.
A friend of mine took out his fathers old M94 rifle in 32Spec this last fall whitetail season. First time the rifle has been out in probably 60+ yrs, maybe more.
It put down a buck at 70yrds or so with one shot, no wandering off. He was impressed. I asked him what else did he expect from a 170gr thin jacketed soft point bullet @ 2100 or 2200fps.