I asked basically the same question last year. You should find this good reading, including an article or two by Bryan Litz
PS.... if you go to JBM calcs and plug in Litz's stuff for the 180 Berger and 180 JLK, you'll see about a 3" diff in drop @ 1000 yds. Essentailly the same BC. My money is on Bryan's work and findings.