My son is stationed at Ft Drum and is home on leave in IL. Can he bring his shotguns back to NY? He has an old Browning auto 5 and a Benelli Super Nova tactical with regular stock. No shell  extension on either. Thanks

Yes he can bring his personally
Owned shotguns to New York as long as they do
Not
Violate the safe act. ( excess capacity thumbhole stock longer than 18" barrel etc)
As a service member I know there are regulations about registering with post storing on post versus off
Post housing and so on which I am sure he is already familiar with. No
Different than if he boxed them up and shipped in his household items when he changed duty stations

State law wise, those two would be fine.

Those two are perfectly fine.
In accordance with DoD regulations, he'll have to register them with the MP's and possibly store them in the Unit Arms Room. (depends and a few factors) otherwise he's good to go.
If he's interested, there are a dozen Clubs in the area that shoot Trap over the Spring/Summer, at least one that has a Winter League, another with Skeet, and Sporting Clays.  Membership is never more than $25. and there isn't a bunch of horseshit with sponsorship, indoctrination, work details, etc.  Membership in the League is $10. and a round of birds $3.
If he Hunts, there are several productive places in the area.
If he's worried about "needing protection"  we're pretty safe up here, and the drug dealers that make the 8 hour trip up here from NYC to sell their wares usually end up a guest of the County...we know who they are, where they shack up, and what they're doing and catch them soon enough.  

If he is in the barracks, he will have to leave them w/ the unit armorer. My unit Armorer(Sgt Del), kept his stuff at my place... No kidding

Keeping in mind I've been on/around Drum since 1987, there have been a few horror stories over the "care and safe keeping" of POWs in unit Arms Rooms.  
The Dealer I associate with makes a trip onto Post a few time a month to collect Handguns brought here by Soldiers un-aware of NY's draconian handgun Laws.
We should grab lunch some time....most days I eat at the 1st BCD "Warrior" Dining Facility.

This was Ft Carson a decade or so ago. But, Thanks for the offer