You can't get a VA loan with a 600 credit score. While the VA loan program has very relaxed credit requirements, VA lenders typically require a minimum credit score of about 650.
The VA loan program is aimed at helping military buyers get an accessible mortgage. However, the Department of Veterans Affairs does not issue loans. The agency only oversees the program and guarantees a portion of each loan. Individual VA lenders handle the actual process, and they require credit score minimums, which vary from one institution to another.