How much exercise?

Do you have any idea what breeds he might be?

My brother gave me the pup, and told me that the mamma is half "feist".  As for the other parts that make the mix, I'd say a little bit of everything.  There was a German Shepard in the area when the mamma came in heat, and Mac does have the facial markings of a Shep, but he's just a little bigger than a large daschund, and has a long, silky shiny coat.  If you can picture a long-haired daschund only bigger, lol!

A feist is an energetic hunting dog.  It isn't unusual for puppies to have the "zoomies" (you'll miss them someday when his muzzle turns gray).  It's just a stage, don't worry.
As to the food you are giving him, frankly, advertising aside, it isn't very good.  If you go to [linkhttp://www.mordanna.com]www.mordanna.com[/link] and click on "The Dog Food Project", you'll learn a lot.
There are wayyyyy better kibbled foods - Innova, Canidae, Solid Gold, Eagle Pack, Prairie, etc.  You may have to buy online or at a specialty store, and it's pricey, but you feed less (not as much filler and empty calories in these foods).

I have two very active hunting dogs.  They are both around 2 y.o. and spend hours pointing, stalking and running in our large yard (I have a radio fence).

 The activities that tire them out the most, though, are agility class and long walks.  I think that it is because they have to think about what they are doing instead of running mindlessly around the yard.

How can I calm the hyperactivity for any training to start?  I've thought about his diet.  I give him Beneful for puppies, about 1 cup per day.  Is this too much?  Too little?  Should I opt for a more protien diet and limit the high carb kibble? 
 

 
I think you're on the right track when thinking about another food. After reviewing Beneful Healthy Growth puppy food, it seems that there is very little meat. You may also see an improvement after the change, but that's not any kind of guarentee..
 
Some foods to look into,
Eagle Pack
Timberwolf Organics
Innova
Solid Gold
Nature's Variety
Natural Balance
Canidae
Blue Buffalo

I'd be interested in hearing how much food others feed their dogs, but 1 cup a day for a medium sized breed doesn't sound like very much to me. My puppy is a Lab, now 8 months, and she gets 3 cups of food a day. She's been getting that ever since I got her at 8 weeks and still gets the same amount, though I switched to twice a day instead of 3 times at 6 months. My other dog, Cassidy ( 3) , is 72 lbs and she's getting only 2 1/2 cups per day. I used to give her 3 cups as well, but she was getting just a little overweight (she was 85 lbs) so I reduced that some. The Vet said she was in great shape with her weight now, so that's what I'm keeping it at. They both get some treats though.

Sorry, I guess I read it wrong, that your dog is a small breed. In that case, I really have no idea how much food the dog should get, so it sounds like you're doing ok. However, I have always fed less than it says to on the dog food bag for the dog's weight, either at the lowest end or sometimes less.

I must agree that there is more to it than quantity of exercise - there is also the quality of the activity...  Running alone will not tire out some pups (particularly really active ones).  Mental stimulation when added to physical exercise will probably help you.
 
I would second the suggestion of enrolling in an activity class like agility or tracking or something like that.  If you can't, I would suggest maybe setting up some obstacles on your own and getting a book on agility or teaching a game like "find it" and then hiding treats or toys all over the yard so your pup has to run around with a purpose.  Our lab x bc is SUPER high energy...  and he is never as tired as after a 15 minute herding lesson.  He isn't running harder or even for nearly as long as when he is just running at the park or something - BUT, the mental focus that herding requires from him, the fact that he has to work with the handler, to follow commands and not run around wildly and aimlessly, it is that concentration, that really tires him out... 

I have a Jack Russell Terrier, which is one of the breeds that make up the Feist (My grandma always alternated between calling her a Feist and a Jack Daniels Terrier). I agree that it's the quality of the exersize, not the quantity, that counts.

Get involved in his games, with him. Start making training games. When it's time for his meal, have him do something for every bite. Mix it up, so he doesn't get bored. Learn about clicker training, and make him figure out what you want. Really thinking about things is the best way to wear out a really active pup. It's not the best idea to get him on big agility equipment, or long runs, or anything too strenuous, at this age. Low jumps, low ramps, weave poles, and things like that would be ok, though. Engage him. You'll both enjoy each other SO much more!