I would say what they were originally developed for.
If they were developed for a hand gun or developed for a rifle.
My 14 inch 45-70 contender barrel does not make the 45-70 a pistol cartridge.
My 357 mag in my marling carbine does not make the 357 mag a rifle cartridge.
Putting rifle cartridges into bolt action hand rifles do not make them pistol cartridges.
Yes things a little grayer now but duel caliber pistol/rifle/carbines cartridges have been around for along time.
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A .357 carbine has very respectable range!