Originally Posted by Deederswy
Oh were you just finding your max load?
Yes. Just max load. Friday I'll be back at it. I'll load 30 rounds or so all at 69.5 gr's, but different seating depths. I'm going to do exactly as Berger recommends.
From Bergers website:
" The VLD (Very Low Drag) bullet design was born from a request made by the US 300 Meter Shooting Team. It was determined that they were dropping points late in the matches due to recoil fatigue. Bill Davis and Dr. Lou Palmisano were asked to design a bullet and case combination that shot flatter than the 308 case and 168 gr bullets the team was using at the time. After a design was created Walt Berger was approached to make the bullet. The 6mm 105 gr VLD was born and shot by the US 300 Meter Shooting Team using a 2” PPC (modified 220 Swift). This combination shot with less felt recoil and a flatter trajectory than the 308 case using the 168 gr bullet and higher scores were the end result. This successful bullet design soon found its way into all long range target competition and the VLD shape spread into all other calibers.
The VLD bullet design is a combination of two very specific features. The first is a boat tail which is common on long and heavy bullets. The second and most important design feature is the long secant ogive. It is this ogive shape that allows the bullet to experience less drag as it flies to the target. This reduced drag is how the VLD shoots flatter and is less affected by wind (less drift) than other bullets. Reduced drag also translates into higher retained velocity. These are important results if you want your bullet to help improve your accuracy by requiring less sight adjustments when conditions change.
For years we have relayed that it is best to jam the VLD into the lands for best performance. This works for many rifles however there are many rifles that do not shoot the VLD well when the bullet is jammed. We have learned that the VLD can shoot best as much as .150 jump off the rifling. VLD bullets can be sensitive to seating depth and it has been found that these bullets shoot best in a COAL “sweet spot”. This sweet spot is a COAL range that is usually .030 to .040 wide.
The quickest way to find this sweet spot is to load ammo at four different COAL. Start with a COAL that allows the bullet to touch the rifling. The next COAL needs to be .040 off the lands. The third COAL needs to be .080 off the lands. The last COAL needs to be .120 off the lands. One of these COAL will outperform the other three by a considerable margin. It has been reported that the VLD bullets don’t group as well at 100 yards but get better as the bullet “goes to sleep” at further ranges. We have learned that by doing the four COAL test you will find a COAL where the VLD bullets will group well at 100 yards. Once the COAL that shoots best is established you can tweak +/- .005 or .010 to increase precision or you can adjust powder charges and other load variables. Frankly, those who do the four COAL test usually are happy with the results they get from this test alone. "