As to mag capacity - many states do limit capacity to 5 - if yours does not fine - if you need that many, perhaps you should practice more though
When is this ridiculous straw man argument going to go away?
OP said nothing of "needing" more than 5 rounds - simply that the equipment he had on hand didn't match a possible 5-round max regulation (that thankfully doesn't exist).
I don't "need" more than 1 round per deer, either, but I still carry extras in my Model '94. I assume most hunters have their 5 round magazines topped off, too. Sure, there may be guys who need to practice more - but that's not the issue here.
And while a 20 round mag may not be practical, if I'm in the stand (with a hi-cap capable firearm) and a couple of coyotes wander by (which has been known to happen) you can bet your sweet bippy that I'm going to unload on them as needed.
Yes, I also plan on buying an AK and and AR-10 and using them for deer hunting, should they show themselves capable within my range limitations in the Texas Hill Country. Will I "need" a 20 round mag? Of course not.
I don't "need" a Corvette either, but it sure would make the commute a lot more fun.
Thank you. I feel much better now that I've had a chance to rant.