165/168 is the optimal calibre bullet wt for 30. ( that's a capital period
500 yrds isnt even long range for a 30-06. I do suppose that heavier VLD's like 180 or 190or 220something would work at 1k with less drop.
+1 To me the word "Optimum" means the best performance a calibre can produce.
If you look at the ballistics for = Velocity, Energy, Trajectory at the maximum distance,using
the same zero they will show you the Optimum bullet weight,
You may chose to use a lighter or heaver bullets depending on use and accuracy but it
would not be at the optimum overall performance.
When I start a project rifle this is the sequence I use to decide what is optimum for the
intended use.
1= Purpose, target or hunting.
2= If it is target ,what type of match and distance.
3= If it is hunting , what type of game and the distance the person will be hunting.( If the
person is not comfortable with a distance there is no reason to build a rifle to fill this need.)
4= Once intended use is established then cartridges that will perform at optimum will
be selected.Of these the person will chose based on preference,recoil,action desired, weight
and other reasons which would be there preferred chambering.even the donner rifle/action
has to be looked at if it is applicable.
5= When all of this has been decided and a load selected as a "Starting point" the build
begins .
6= When finished load testing begins with the selected bullet weight and style.
In your case you already had the cartridge,intended use,maximum distance you wanted to
hunt/shoot so the optimum bullet weight @ 500 yards would be the 160 to 170gr class of
bullets because of downrange velocity and energy.
The lighter bullet in your calibre will have a flatter trajectory but less energy, a heaver bullet
will have more drop at the distance you chose and less velocity and energy. And at 500yards
the wind bucking ability is insignificant.
So when I use the term optimum It is just that. I may chose to go above or below but that is where I start.
Normally I will chose to go a little heaver that optimum if I do change bullet weights but that is
rare.
At extreme distances heavy bullets are best as long as you can get velocities high enough to
stay supersonic at the extended distance. so look at all aspects of performance and compare
apples to apples and don't change the parameter's to make a round look better. IE: if you
compare performance use the same zero,you can always change it after the selection is made
to suit your needs or preferences.
I hope this will help you decide which bullet is best for your needs.
J E CUSTOM