COAL and 95-grainers

[6mmNewB]

Ok, I will give you what I would do or one way to proceed that you might not have thought of and a little theory as well.  First, barrel vibration or harmonic nodes occur around every 0.006" or so.  This varies due to many things like barrel material, diameter, length, etc...  Hence, there is no magic number that you can just seat a bullet that will do good things except by shear luck.  There is a way to reach your intended working accuracy potential.  Here is one way, someone might proceed.

Here's the thing.  This all turns into a timing issue.  A barrel will vibrate when the cartridge is fired very much like a steel pipe if you strike it on one end with a hammer.  This vibration runs up and down the barrel and diminishes over time, a very short amount of time.  Very good accuracy happens when the projectile exits the barrel  while the barrel is going through the zero plane during its ringing cycle.  If the bullet exits while the bore is pointed elsewhere, the bullet will go elsewhere.

One way to find the best a given bullet, powder and primer combo will perform is to fine a more stable combustion node and then tune the bullets timing with seating depth changes.  Here is a quick look into one such method.

Start with loading some cartridges with the same bullet at the same length and charge the cases with 0.3 grains of increasing powder charge from a safe starting load up to a max loading point.  Just one round each charge weight.  Shoot these over a chronograph and write down the charge weight and the velocity for each shot.  When done, look at the data and look to see if you can find a place where increasing the powder only moved the velocity a small amount.  This might happen in several places in your data.  Something like: charge x = 2770, charge x+0.3 = 2800, charge x+0.6 = 2807, charge x+0.9 = 2832.  A stable combustion spot might be between the +0.3 and the +0.6 load.  Lets say x+0.4 or x+0.5.  This is where a little more or less powder during charging will have a small affect on your velocity.  Example: lets pick a powder charge of X +0.5 grains for the stable load.

Once a stabled combustion load for that powder/primer and bullet combo has been found, the seating depth tests can be done to find the seating where it all comes together.  Start at some point off the lands or away from sticking in or jamming into the lands by at least 0.010" maybe 0.020".  Load some rounds, each loaded with our example of X +0.5 grains of powder, at several lengths down from that point in 0.003" increments.  An example: lands at 2.200", start at 2.180", 2.177, 2.174,  etc. Load 5 rounds at each depth to test and shoot each seating depth group on paper.  The best group (depth) will point to the more correct seating depth. There is NO magic number for this.  It will be different in every rifle with every powder and every bullet and yes even every different brand of primer.   

Looking at this info, it can be understood why folks try to find the bullet that they want to shoot and the powder that they want to use and proceed through the testing to find the load that their rifle shoots the best, then try to stay with that same load.  This is not to say that one can't work up a different load with different powder/primer/bullet and put two, three or four recipes in their reloading book.  To change anything in the combustion timing sequence, and the projectile simply will not be at the right place at the right time on exit.  

I don't know how many want or need this level of potential accuracy.  ( potential, because this chosen powder/primer/bullet just might not shoot in the test rifle ). With the way components are these days, simply finding a good load might be good enough for most needs.  I know this is more info than the OP asked for, but there is a reason for testing primer/powder/bullet combos and moving the seating depth around.  I have simply tried to explain what I think it does and why it matters.  Since the OP looks to have bullets of the same weight, finding a good stable powder charge first, then a seating depth might be found that works well with all of them.  There is a difference, but good notes in a log would at least allow for keeping most things the same and only a small seating depth change when loading a different 95 grain bullet.  If I remember correctly, Velocity will move the bullets up and/or down on the paper, Seating Depth will open and close the group size.  Or a tuner will solve the issue. Simply remember the setting number for each bullet you tune it for.  Easy!

Enjoy and have fun!  Its all good.

Thank you for taking the time to share your knowledge. Excellent information!