Re: velocity spread
Powder charge changes are the biggest determining factor in changing ES/SD.
All of the other things will fine tune it.
What cartridge, powder , bullet, oal are you using and what numbers did you get at other powder charges?
I work up to a max load by using velocity, case head expansion, primer condition, bolt lift,extractor marks or lack thereof. As well as temp, OAL, whether it is on the lands or off and of course published data and my quickload data.
Sometimes MY max powder charge for a particular combination is well Below book max.
Case in point was a savage 270wsm. With 140accubonds and imr 7828 I was 2gr below published max as my max in my particular setup. I was well off the lands too!
Sometimes MY max powder charge for a particular combination is Above published data.
Especially when I am loading to a much longer and still off of the lands.
Even different lots of the same powder may have a different max charge. Different case capacities of various brass,primers, etc.
Every rifle, bullet, powder combination is different.
I mostly test at 565yds and want a load with a 1.5 inch so of vertical at that distance.
I guess it was a long winded way of saying to try different powder charges.
You may find a great load lower or maybe even higher.
Just stop when you should and don't push it too hard at the top.
I work up pretty high and I have never had to bang on a bolt to open it or had a primer blow out.
It looks like you are doing things right, you should be able to bring the es down at least another 10 or more fps.
Last edited by RockZ; 02-14-2011 at 11:14 AM.