Everything is mixed brass, S&B primers, N320, LOS 145gr plated 9mm, AOL 29mm
First string 3,55gr N320
average velocity 884.6fps PF 128
st dev 15
max spread 48fps
Second string 3.65gr N320
average velocity 904.2 PF 131
st dev 20
max spread 75fps
however I must have messed up one charge (took 10 random bullets out of my vault) because if I deleted 1 abnormal low velocity shot in the second string, I got:
av vel 910fps, PF 132
st dev 8
max spread 27fps
The VihtaVuori does not give numbers for using 147gr Ranier plated with N320.... which is one reason I suggested N330. As a new reloader, I'd go back to the 3N37 just to be safe. Or move to the 124gr bullet which does have numbers for N320.
Here's the problem with N320.... With 115gr Ranier the load "window" goes from 3.9 to 4.4gr, or a total window of
0.5gr. With 124gr Ranier the window goes from 3.8 to 4.1gr, or a total window of
0.3gr. In other words, as the bullet gets heavier, the window using the same powder gets smaller. So the load window with 145/147gr might be a total of 0.1 or 0.15gr !! Another way to state that is that your margins for error greatly diminish,
and your risk greatly increases. And you've got no numbers from Vit to guide you, so chrono numbers mean exactly zero.
However, N320 with 124gr bullets works very well. As I explained earlier, becasue the data is collected in longer barrels, the loads can go slightly higher than those listed. Your friends that told you otherwise were only looking at the load manual, not the chrono reports.
The only other option you have is to call Vit and ask for data on N320 with 145 gr bullets. They may actually have it. You must get the velocities with the loads. Then you'll have data you can relate to your collected data.
Hope this helps.
PS. I agree with dropping data points that are obviously errors.
