Thread: Testing a conventional approach to load development

Originally Posted by STC

Barrel cooling does matter, as do plenty of other factors, how much they matter? that is not exactly known. Getting up and changing your shooting posture, has an impact. Parallax dialled out will minimize parallax, not eleminate it completely. fouling can change things too. All minor effects, that generally are not too important when dealing with general hunting precision requirements. But when you are looking at 0.25 or 0.5 moa differences, these minor influences do start to matter. Another thing is poi shift: since you fired all those shots into the same group you would not know if later 5 shot groups had a different poi, compared to earlier ones. So even if one of them was tighter to start with it would be hidden if any poi shift occured. Essentially any "signal" (if it is there) is hidden within other "noise", and thats why both of them show no significant difference.

Not saying you are a bad shot or anything (you clearly are not!). Essentially what you did is try to "prove" that for 2 charge weights, both of which already shot very well in your rifle (for general hunting purposes) there would not be a difference, (despite 3 shot groups indicating that there would be) by introducing a many other factors uf unknown impact into the system.

Your system here (rifle, loads, you) seems to give good (

Ok so there are several layers we're going to have to get through.


1. What is a sensible procedure for establishing the practical precision capability of a rifle system?
2. What is a sensible statistical test for comparing data when changes to the system are made, to detect whether or not the changes have resulted in a meaningful change in precision? (in this case the change to the system is a small difference in powder charge)
3. What is a sensible approach to load development?



Let's start with number 1.


What is your proposed approach for establishing the precision capacity of a rifle system? Defining rifle system in terms of the way that it is practically used - shooter, rifle, scope, and the specific ammunition.

What metric would you use? How precise would you expect your estimate of the precision capacity to be?