Big differences in VV data


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Zak Smith
January 19, 2003, 03:10 PM
I am looking at two different Vihtavuori manuals. The first is an exerpt dated 2000 in my LoadBooks compilation of 9mm data. The second is the PDF file from vihtavuori.fi (http://www.vihtavuori.fi/USAguide.pdf) (dated 1/2002).

The first manaul, which has data from what was probably the 1st edition of the VV book, has starting loads way above the "MAX" loads in the second manual. The OAL for the loads are the same, but the case and primer differs. In the first manaul, it's LAPUA brass and CCI500 primers. In the second, it's Remington and "Small Pistol" (Win??).

For example, take the 115gr XTP @ 1.142".

For N320, the first book lists 5.3 (1170fps) - 5.9 (1303fps). The second, 4.1 (1135fps) - 4.6gr (1206fps).

For 3N37, the first: 7.2 (1340fps) - 7.9 (1423fps). The second, 6.2 (1237) - 6.9 (1328).

These ranges don't even overlap! The first book does list the pressures for the "MAX" loads (36.3kpsi) and the newer book does not. Is the decrease due to watering down of the loads to avoid blowing up old guns?

FWIW, I have used the "old" data for loading 124gr Gold Dots, and the velocities I got were within less than 1% of the published values, as described in this TFL thread: Some full-power 9x19 data (124GD/VV-3N37) (http://www.thefiringline.com/forums/showthread.php?s=&threadid=131703).

thanks
Zak

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Zero
January 19, 2003, 08:53 PM
I believe as a general rule. Europeans reload a little hotter than the folks over here. So their data can sometimes be on the high end. I'm guessing the new version of the manual was brought more in line with "American" standards, thus the reduction in powder, pressure, etc.

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