Here's a picture of a gooseneck round which is the bottom and rump and eye of round together:
You separate off the eye of the round and heel of the round and you're left with this:
If you follow down the right hand side you come to a right angle notch before it goes to the point. You'd separate it at that notch by cutting across it so the point is one piece and leaving the rest. You've now separated the rump (point) from the bottom round. However, if you look at the rump, you can see a similarity to a sirloin; that's because off that point is where the sirloin comes from. The bottom round is used in the leg but the rump is used in the ..well. rump or fanny (ass) of the cattle, which is not load bearing and doesn't get exercised that much, no where's near as much as the bottom round (leg) of the animal. You can cut off rump steaks from it and they're almost as good as sirloin. Try it with bottom round and they're almost as good as Red Wings, lol! Dutch is absolutely right.
As far as the most tender? Not necessarily. You can roast a sirloin tip or a whole sirloin shell, (top butt) for a more tender roast, but for practical and mainstream economic reasons, a rump is a great dinner roast!
Bottom round is best suited for swiss steak when cubed or cubed steak, stew beef, or pot roast (wet method vs. dry method or tenderized). Or, from a smoking viewpoint, it makes excellent dried beef also as it's cured, smoked, then sliced paper thin! You can also make jerky out of it if you have stout teeth (or diamond steel false teeth, lol!) when sliced with the grain. Across the grain would definitely be better, however!
