What part of the state and what kind of hunting? Ive hunted deer here for 25 years. Some places/styles limit you to 75 yards or less, in which case something like a 450 bushmaster is ideal (not easily deflected bullets, more kinetic energy, etc.). Other places where a 300-400+ yard shot can happen, a smokeless 45 cal muzzleloader is ideal.
Dont overlook a 444 marlin if you can find one (my brother uses one), but I still run a savage 220. Good to ~200 (maybe a smidge further if you practice it).
I’ve shotgun and muzzleloader hunted in Iowa for the better part of a decade and can say I’ve shot 0 deer over 100 yards, not because I’m a poor shot, but because a good opportunity has never presented itself (mostly hunted with groups, walking sections). If you’ll be gun hunting with a group it’s nice to have a repeater of any sort. 450 bushmasters, either AR or the Ruger American models have become extremely popular. Lever action 45/70s are also very popular. If you’re still-hunting alone a muzzleloader or the savage 212 or 220 are excellent choices. Best of luck this December!
I would run a muzzleloader for a couple of reasons. Not knowing your hunting style, area, other states, current firearm selection...this will just be a general answer.
You can get a very accurate muzzleloader setup and then use it in other states during their muzzleloader seasons.
I’ve got a Thompson setup with crosshairs in the front hood and Lyman peep rear that shoots 4” at 200yds and 10” at 300. Use blackhorn powder and Thor bullets that are lathed to your guns specific bore diameter. With a scope you could really dial in with drops etc. I’m just not familiar with Iowa laws about optics on muzzleloaders.
Still hunting a custom muzzleloader would be the best bet IMO. If still hunting somewhere with no opportunity of a long shot a slug gun/straight walled cartridge would be fine.
Party hunting I use 2 different shotguns, both with slug barrels. A Beretta pintail semi auto with 3-9x scope, which I can shoot to 200yds or so. I use this gun while sitting on drives that overlook fields with the possibility of a longer shot(80-200yds). 2nd is a Benelli Nova with only iron sights I use for driving deer. While pushing/driving your shots will typically be within 50yds.
i recently purchased a ruger am. in 450 bushmaster for ohio, good price and good shooting gun. my first one was a 6.5 creed for a truck gun for dogs and such the scope was more than the gun and it shoots little holes. you might also look into the new winchester offering the 350. i have read some about it and it sounds good.
Always use every opportunity to buy a new gun. Marlin 1895 in 45/70, or AR 450 Bushmaster. The 450 uppers seem to run on any standard lower but cowboy guns are way cooler. And for bragging rights - Marlin's web site shows their 1895 SSBL rated to handle all North American Big Game, including the T. Rex from Jurassic World