I may start working in this direction after my final round of accuracy testing with the RMR 69 grain BTHP. I seat them to 2.245" as Shooters World uses that as their COAL. If I wanted to move up to 2.260 for testing, what increments are used? Is 0.005" too small?
Increments for Testing Seating Depth and Accuracy
- Thread starter DMW1116
- Start date
Blue68f100
Member
I normally use 0.005" when I'm checking OAL accuracy. In some rare occasions 0.003" is better, or if you see a change with 0.005". You way want to see how larger the window is.
What I have adopted for my load increments is 1% of MAX load.........so for example, if it was 40 grains powder, 1% is .4 grains, starting at max and backing down in steps. About 5 or 6 ought to be enough.
For seating depth, if I'm going to do it, is I strip the bolt, then find the seating depth where the bolt will close on the seated bullet........aka, the lands. Then back up another 10 thousands as my starting place, then increase seating depth by 3 thousands per increment. Also 5 to 6 increments.
For seating depth, if I'm going to do it, is I strip the bolt, then find the seating depth where the bolt will close on the seated bullet........aka, the lands. Then back up another 10 thousands as my starting place, then increase seating depth by 3 thousands per increment. Also 5 to 6 increments.
I use 1% for charge weight or 0.2 grains, whichever is greater. My scale isn't precise enough to bother with 0.1 grain increments. If I decide to keep tweaking the RMR HPBT loads, I'll try 0.005" increments. The corn cob tip probably means anything smaller isn't reproducible.
Chuck R.
Member
This is a sample of the formula I use based on a comparator reading of a bullet in the lands:
So basically backing off .015 initially, then in .010" increments. For all coper bullets I start at the Barnes recommended .050 for my initial.
So basically backing off .015 initially, then in .010" increments. For all coper bullets I start at the Barnes recommended .050 for my initial.
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