I'm like a little kid when it comes to digging into the berm trying to recover bullets.

The biggest difference that I see in shooting dirt versus something wet is that the bullet will expand, but might not fragment like it would in game.

A few years ago, I recovered about 30 out of 40 shots from my .44mag Hornady FTX's one day, weight retention was amazing, expansion was HUGE.

Hornady Leverevolution 225grn FTX .44mag into dirt at 50yrds ~1200fps:



Shot a deer with it, much more fragmentation. The next pic is of a 325grn .45-70 Leverevolution FTX instead of the same .44mag bullet, but the results I've seen with the .44mag on deer looked very similar to this. I pulled this bullet out of a deer hit at 250yrds, which out of my wife's Guide Gun was trucking about the same speed as that .44mag was. The bullets I've recovered from deer with the .44mag FTX look pretty similar to this, a bit more weight retention in general with a prettier mushroom, but actually pretty similar to this.

Hornady Leverevolution 325grn FTX .45-70 into a deer at 250yrds ~1150fps:



I suppose it'd be fair to judge expansion of bullets side by side by shooting into dirt, but I'm not 100% sure it'd really tell you what you want to know about performance on game.

EDIT: Sorry for the terrible quality pics, these were taken back before smartphone cameras were worth a damn...