Originally Posted by mo
Thanks for your comments. Sounds like you can take some guess work, and a little leg work if you use a chronograph.
Before I started using a chronograph Testing was hit and miss,I had one rifle that I just could
not make it group (I tried over 70 different loads) .Frustrated I decided to start over and shot
some of the left over test rounds through the chronograph and tryed to figure out what was
The third load I shot had a standard deviation of 09 but grouped terrible ( almost 2"). so I went
to a SMK of approximately the same weight to eliminate the chance that the hunting bullet was
of poor quality. The SMK shot almost the same so I was back to square one.
Not knowing what to do next I decided to try different bullet seating depths with the same load.
I started .050 thousandth off the lands and moved closer in .010 thousandth increments
watching pressure signs.
The closer I got the better it shot up to .020 thousandth. .010 did not shoot any better and .005
gave me signs of pressure.
Different Bullet designs may dictate seating depth so you just have to experiment once you have
a good powder,primer,velocity and bullet weight combo (Lo SDs).
This rifle is a 30/338 and will shoot sub 1/4 MOA groups all day long so using the chronograph
saved a great rifle that was destined for the donor pool.
Since switching to this method for working up new loads I have cut my time and cost by 75%
and with prices now days that's a big plus.
Don't get me wrong you can still find accurate loads buy trial and error and maybe luck out with
only 1 or 2 tries but if you use your chronograph you will also build a good data base for trends
with different loads.
I use the chronograph to eliminate bad loads that would never shoot well and work on the
ones that show potential.
This is just the way I approach load development.
J E CUSTOM