Just checked your Iowa Requirements, and this fits the criteria. Nothing I read says it has to be a "Pistol Caliber".
"
Rifle Equipment:
- Centerfire rifles .357 caliber or larger, shooting straight-walled ammunition with an expanding-type bullet where:
- Straight-walled, centerfire, rimless cartridges have bullets that are from 0.357" to 0.500" in diameter and have a case length from 0.850" to 1.800"
- Straight-walled, centerfire, rimmed cartridges have bullets that are from 0.357" to 0.500" in diameter and have a case length from 1.285" to 1.800"
- Those centerfire cartridges that are listed as legal in Iowa’s hunting regulations"
It's .357" caliber, and the straight walled rimless case length is 1.71". Fits the criteria. So does the .450 Bushmaster (amongst others), and neither are classified as "Pistol Calibers".