Waterfowl hunting regulations are pretty clear that you can't be in immediate posession of lead based ammo while hunting waterfowl.

Recently the bear population has increased dramatically around here (grizzly bears)  many of the places we hunt are now prone to having bears in close proximity.  I was thinking it might be a good idea to carry a couple 12 ga slugs in case you find yourself in an area where there may be a bear.  It would be more of a oh shit we probably ought to work out way out of this area because something is not right, load a couple slugs and beat feet.  Obviously in an actual bear encounter you would not have time to unload and load.

Question is how much trouble are you going to be in if the fish and game cops do a license and ammo check and find you in possession of a lead slug?

https://www.basspro.com/shop/en/winchester-super-x-lead-free-rifled-slug-shotshells

They're gonna hang you.  Even if you tell them the bear protection story.

If you're really worried about the bears pack along a super-magnum revolver.

Sadly I think you're correct.  I guess they could argue you could be sniping at stationary geese at long range.

Carry lead free slugs or Tungsten buckshot.
Either way, you're still in possession of shot larger than F size, so against federal regulations for waterfowl.
I'd place a phone call to both the state and USFWS wardens in the area you primarily hunt and discuss what your best option is for lethal bear protection with lowest risk of getting a ticket.

as others have said....no tox shot.  Heck, solid copper slugs have been sold in big box sporting goods stores for years.

can't you carry a handgun with you and keep it concealed? If you call the wardens they will probably tell you carry pepper spray.

Virginia specifically allows CCW while hunting, if you've got the permit.