3 cups butter to quickly fry/season the beef
25 bottles (5 ounces) Hormel dried chipped beef, which is about 8 pounds OR 25 bags (4 ounces) of Armour dried beef, which is about 6 1/2 pounds, soaked, drained, and rinsed- discard soaking water. SEE NOTE.
6 cups butter for roux
6 cups Wondra flour for roux, OR 2 pounds regular all purpose flour
1 tablespoon cayenne pepper
1 tablespoon Black pepper, OR to taste
2 tablespoons nutmeg or mace (I prefer fresh nutmeg)
4 gallons half and half or whole milk
6 pounds of cream cheese at room temperature
3 tablespoons Worcestershire sauce

NOTE; The dried Armour beef is drier and denser that is why the difference. Hormel makes a restaurant pack of 3 pounds, I would use 3 packages. You can also use 25 pounds of 80/20 ground beef or ground turkey instead of dried beef., but then cut the second add of butter in half.

Soak, drain, rinse, pat dry and chop the meat. Cook in the 3 cups butter. When flavored and dried, add second add of butter and sprinkle on flour. Stir thoroughly and and cook at least 5 minutes until smooth.

When ready, begin adding the milk or half and half, whisking smooth with each addition. Bring to a low simmer, keep whisking, a leas 20 minutes. Add the cream cheese and keep whisking til smooth. Hold over a low heat.

Yes, you can omit the cream cheese, but adding it makes this dish silky and delicious. You can also make thicker or thinner sauce by varying he amount of half and half or milk.

See this article for a look at SOS in the military messes:
www.seabeecook.com/cookery/cooking/cooking_sos.htm