Last year I read a post on understanding bullet patterns, and can not find it to save my life. Unfortunately, I have lost a lot of data and ref material that I had accumilated over the last few years.
This is what I need to know. When working on starting loads, someone had written a great post on relating the bullet pattern to seating depth and charge. As an example, if your 5 shots run a diagonal straight line Vs an arc, or a triangle. I haven't work on any new loads in a long time, and I have a 22-250 that is giving me some grief.
Win brass, WLR primer, V-max 55gr, H380 @ 37.8 seated .035 off the lands produces a 1" group that is a diagonal line running on a 45 degree angle from right to left.
The exact same pattern is also produced (near perfectly) with the change of the charge increased to 39.0 with a seating of .045
If I decrease the charge, and move closer the lands, I get the same result, but not improving the pattern.
Running the same load info, but going to a CCI and Fed 210M primers, I get a "box" pattern with increased pattern size.
I have been increasing/decreasing the bullet seating in .005 increments with a constant beginning charge. Once I have the best pattern with a seating depth, I run the charge in .5 gr increments to get the best pattern. From there, its small tweaks for improvements.
I'm in a rush because of work and lack of time. I have 2 days left to get a reasonable working load for a p-dog shoot. The post I had read did a great job of explaining the relationship of the bullet pattern to what is going on. Made it easy for adjustments (faster, slower, bullet not stabilizing....)
Can someone help?
