With that cannelure, likely a .357" bullet made for revolvers. Having some 158's come along with it pretty well offers a bit more proof. Probably could safely work in a 9mm,but likely a little less than max. loadings. Were a lot of 9mm semi-autos with larger than 9mm bores. Exposed soft lead noses aren't known for great feeding in 9mm semi-autos.
Long ago, Speer did make a RN jacked soft point 9mm (haven't looked...assume they dropped that offering), even factory loaded ammo. Some pistols would feed it (pretty much matched the FMJ profile).
I'd have to experiment a bit, looking for functioning rather than trying for the last few foot pounds of power.
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