Brown ground beef and onion in skillet on medium until brown, breaking up the ground beef as it cooks, about 10 minutes.
Drain excess fat from pan and return to heat.
Add Velveeta and cook on low heat until cheese is melted and evenly distributed, stirring frequently.
Remove meat and cheese mixture from heat and transfer to a bowl, stir in pickles, mustard and Worcestershire, and combine.
One by one, fill spring roll wrappers with meat and cheese mixture. To make the perfect spring roll, place wrappers on your work surface so they are in a diamond shape. Spoon about 1/4 cup of the mixture onto the lower half of the diamond, leaving room around all the edges. Starting at the bottom wrap the spring rolls tightly tucking in the ends as you go. To seal moisten the top corner with a bit of water and press to seal.
Fill a deep frying pan with 1/2 inch of vegetable oil. Heat oil to 325°F (160°C). Fry the spring rolls in small batches 2-3, being careful not to crowd the pan. Cook 2 1/2 to 3 minutes on each side until crisp and golden brown. Remove from oil and place on wire rack or a plate lined with paper towel.