AFAIK it is a common experience that both C and C++ code tend to become fewer LOC in a move to Rust, a lot of it due to stuff like serde that greatly reduces boilerplate. It probably depends on your application and program size, though. I'm sure that if you're doing a lot of pointer wrangling or something it won't be smaller in Rust, while if your C program was just a bunch of SIMD intrinsics anyway like a lot of high performance code is now it'll probably be basically the same length.
Did you ever take a look to try and figure out where the extra verboseness came from? For instance, was it spread equally across all functions or concentrated in those doing numeric computations (or whatever)? It would be interesting to learn something from this example.
Did you convert it by hand and translate the code into idiomatic rust? Or just run some C code through c2rust? Because the latter will not produce anything like a typical rust program, it will be C types and logic with minimal changes to make it compile in rust (and those changes will make it look very verbose).
Are you just noting specifics, or was it your experience that there was less Rust required for a full C to Rust conversion?