What caliber is my rolling block

[Logangrimnar]

So I posted earlier about the rolling block that I purchased hated with an obviously new replacement barrel. It is definitely a remington. It has the number 529 on the top and bottom tang. No other markings (serial number?)
The rifle was sold to me as a 38-55. I slugged the bore by driving a sinker through it. It measures 356! Obviously not a 38-55. Any guesses? I'm probably going to have to chamber cast it but thought I'd ask.
Richard

[Logangrimnar]

Seems straight walled or at least no bottle neck. Case length without bullet will be 1.680 or close to it.

[Trailrider]

Rimmed or rimless? Maybe a 9.0 x 47R. Make the chamber casting. Might be able to use .38-55 brass.