Received the 6mm's today and I'm a little disappointed. NOT in Sierra, though. Midway USA had all the specs on this new bullet listed EXCEPT for the length. I was suspicious when I opened the box so I measured 10 of them to get an average length and then plugged that and other parameters into Berger's Stability Calculator. "Marginal Stability" is the answer I got. So, once again my choice of a 1-9" twist barrel (and my lowly 500 ft elevation) put the whammy on me. Should've just stayed in Colorado when on vacation there last year!