Yesterday I ran a few CCI 30 grain V-max through my 6" AMT and my BRNO 611 rifle. I was surprised to find that from the AMT the velocities averaged about 100 fps slower than CCI 30 grain HPs I have previously tried. From the AMT I got an average of 1584 fps with an extreme spread of 109 fps between the fastest and slowest for a standard deviation of 43. Groups at 25 and 50 yards were about average for this gun, neither the best nor the worst. For comparison, CCI 30 grain +V hollowpoints averaged 1639 fps with an SD of 26 while CCI 30 grain TNTs went 1689 fps with a SD of 18. The TNTs are the only ammo that has not been 100% reliable in the AMT, sometimes the wide mouth hollowpoint will hang up on the left side of the feed ramp.
From the 20" barrel of the BRNO, velocity of the 30 grain v-max jumped to 2224 fps average for five shots but the extreme spread also jumped to 213 fps for an SD of 89! That is the worst extreme spread I've ever gotten from .22 rim mag ammo. But the targets told a different story. At fifty yards two groups of five shots went 0.63" and 0.75", two of the best groups I've ever gotten from that little semi-auto! So much for SD as an indication of accuracy! Now I do suspect that velocity spread would have resulted in vertical spread at 100 yards but I didn't try it as the wind was starting to kick up and I doubted I could get any sort of group at 100. I've yet to find any ammo that won't function just fine in the BRNO.