I tried my first OCW test recently.
If you're not familiar with it, you can get up to speed atDan Newberry's OCW Method (http://www.ocwreloading.com/).
This is a 308 Norma using 168 grain Bergers. The powder is IMR 4955. Fiocchi primers.
(https://ysterhout.net/images/ocw/308-norma/4955-71.jpg)
(https://ysterhout.net/images/ocw/308-norma/4955-72.jpg)
(https://ysterhout.net/images/ocw/308-norma/4955-73.jpg)
(https://ysterhout.net/images/ocw/308-norma/4955-74.jpg)
(https://ysterhout.net/images/ocw/308-norma/4955-75.jpg)
Based on this, I decided that 73.0 is the charge I'm looking for, because it's in the middle of a 3 percent range where the groups share the same center - on this test - they are identical.
Co-incidentally, that charge is what I've been using on the gong shoots, with very consistent impacts to 600 meters. This test is pretty much showing that it is a stable charge weight as far as point of impact goes.
To verify this test, I intend to re-shoot the 73.0 grains charge, with half a percent above and below, and check if the groups center in the same place again. If it does, then I'll move onto a seating depth test.