First: this is amazingly simple and good information:
Second, you were right on track here, but I suggest a 700 MilSpec in .308Win, as your first thoughts on the durability and use of the pump and bolt action are good:
I can tell you from hands on real world experience with looking at harvesting game, from small white tail deer to moose & elk, the .308Win outperforms the 6.5 Creedmoor by a little bit. That's just my mileage, as yours might vary. That is also using the 6.5 and .308 calibres to their advantages: 6.5 for deer on open prairies and 308 for everything. Just everything. I carry a .308Win, where legal (not in parks) with hand loaded 220 grain Sierra round nose bullets should a bear or other animal be a threat against my life.
EDIT - Number one tip when doing scopes and mount: Don't let anyone mount the scope too high. You need proper cheek weld to be a good shooter when hunting. Any large diameter scope (like bigger than 42mm objective), in my opinion, requires a cheek rest adapter, riser, pad or something. Again, advice is worth what it is... free.
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Now, shotguns are something different. The plastic adjustable stocks are great if you plan to share it with those of different body sizes than you, or want to get a combo gun with both the long choked barrel as well as a very short barrel. The basic Mossberg pump shotguns, with both barrel sets, are great and no gun owner should be without one.
When you get into wood stocked guns there is non-adjustable measurements, a slew of them. In a rifle a lot of the time using scope bases and rings can adjust how to aim a rifle to fit you. A shotgun does this by these non-changeable measurements. Fit of a wood stock shotgun is paramount. Here is a good guide for you to read some time: https://www.theyorkshiregent.com/sho...e-fit-shotgun/
The super shortened explanation: a solid stock (plastic, fibre glass, composite or wood) is best, and unless you are a very generic person trying out, swinging and mounting the gun to your shoulder is mandatory. The top two things that keep me in a store trying, trying and trying out over and over again is: second, buying shoes... and first, buying a shotgun.
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So, you will get lots of advice. Most gun owners buy a few, sell a few, and learn their likes and dislikes. Your gut instinct went with the 590: my opinion, is a good choice. Your first instinct was the 700: my opinion, that's a good choice too.
Oh, By the way: big disclaimer. Cause this is great advice too: