Running .32 H&R/.327 FM in a .30 Carbine Blackhawk

[djw]

I have an unconverted OM .30 Carbine Blackhawk. I've seen discussions about how one can shoot .32-20 in the NM, but that there is a clearance issue at the rear of the cylinder in the old models. I don't have anything (or interest) in the .32-20, so that's not an issue for me.

However, what are the issues with shooting the .32H&R or the .327 Federal through an OM .30?

Here's what I see:
First, the bore on the .30 Carbine Blackhawk is supposedly .308, while .32H&R bullets are ~.313. However, .32-20 bullets are also .313 or so.

Second, the .30 Carbine case tapers from .356 to .336, while the .32H&R is a straight .337.

Third: Both .32's are shorter than the .30 Carbine, but the rim on the 32's hold the case in position for the primer to be struck, maybe too well, as the cases don't recess below the firing pin groove, as shown here:


Are any of these concerns justified, or is this just not a good idea?

Thanks.
Don

[the priest]

The .30 carbine runs at about 32,500 psi. The .327 over 40,000 psi iirc. Add in a bigger bullet going through a pipe that's smaller and you have even more pressure. Draw your own conclusion.

There's nothing the other two are going to do that can't be done with the carbine.

Last thought; ill bet accuracy would suffer and cases will split unless you were to get another cylinder.

All my thoughts,.....but if it were me,.....I would save for another revolver.

[texashoosier]

The .32-20 has a diameter of .344" above the rim; the .32 H&R and .327 Federal is .337". The .30 Carbine is .356". That's a difference of .019" and, IMO, an invitation to a case split given the pressure the .327 operates at.