Depends on the load. I shoot the 300gr Nosler partition/H4198 at 2425fps in a 22" .45-70 barrel, the same load in a 32" barrel only makes 2450fps.
The 350gr Hornady RN at 2027fps with H322 in the 32" barrel, and 1850fps in the 22" barrel.
Another comparison is IMR4198 and the 350gr Speer FP, 1932fps for the 22" and 2082fps for the 32".
Tim