RJY66,
Let me see if I get this right: You could see the bulge of the bullet under the hide on the far side of the deer, and a "pretty good-sized chunk" was left. Yet the bullet had "pretty well disintegrated." These seem to be mutually exclusive statements.
Yes, many lead-cored bullets fragment to a certain extent. Despite the beliefs of many hunters about how much weight a bullet should retain, this PARTIAL fragmentation makes a bigger wound channel, and on average kills quicker than bullets that don't lose much weight.
I've shot a bunch of big game animals with Hornady Interlocks from .25 to .338 caliber. The average retained weight of the relatively few recovered bullets has been just about 50%, varying from around 40-60%. They were all recovered on the far side of dead animals.
