In the deer I've killed with Foster Slugs the slug isn't usually recovered. Penetration on broadside shot in 200 lbs Whitetails is typically complete.

You didn't say which species of bear you were conerned with, but the one Black Bear killing I was in on with a slug had already been wounded but was finished of handily by my old man with his Remington Model 11.

Brown Bears would be a different story I bet...