Those were actually averages from around 14-16 rounds, not 6 or 8. I had a few I had to cull because of bad readings. And I found that the 2400 was shooting kind of dirty too, with a little unburned powder left in the cases, so I think that some unburned powder was also traveling out of the barrel too and possibly interfering with the reading. One string I shot I had to cull because over half the readings were a little more than 1/2 the expected velocity in the 600-650 ft/sec range. When I backed the chrono further out around 3 feet those went away.

BTW, I'm not trying to be overly scientific with this or trying to make some competition ammo or anything. I'm just out having fun and putting rounds on target. And sharing some info here, as many times I see people post up stuff here and assume some velocity for their load with no scientific basis to establish real world results. I think that next time I play with these I will use Accurate #9 instead of 2400 for my powder, as I've found it burns more completely than 2400. And I will bring my Rossi 92 to compare the ammo betwen a short barrel pistol and a 20" barrel rifle.