In a Dutch oven, combine beef and water.

Bring to a boil over high heat.

Reduce heat to low, cover, and simmer for 2 hours, or until beef is tender.

Remove beef from the Dutch oven using a slotted spoon.

Shred the beef with two forks.

Set the shredded beef aside.

Skim the fat from the cooking liquid in the Dutch oven.

Stir in ketchup, Worcestershire sauce, lemon juice, horseradish, mustard, and salt.

Add the shredded beef and shredded cabbage to the sauce.

Bring the mixture to a boil.

Reduce heat to low, cover, and simmer for 45 minutes, or until cabbage is tender.

Spoon 1/3 cup of the shredded beef and slaw mixture onto each sandwich bun.

Serve immediately.