ES, SD, and seating depth relationship?

[broncman]

For years I have done a ladder style workup for new loads. Lately I am second guessing that. Seating depth can greatly vary the accuracy and change poa.

Now that I am starting to shoot F class matches at long range, SD,and ES are major role players to keep verticals tight. After reading the "12 pack" load development article in the latest Shooting Times it brought out some questions.

I know seating depth can alter pressure . What effects on SD and ES does it have?
If you have a load with good SD, and ES, andd you alter seating depth, does it change?

Could seating depth alterations bring a load we passed on previously into the keeper zone?

 

[RDavies]

Yes seating depth can certainly affect the ES/SD. The only uncertain thing is which way to go. I have some calibers which must be jammed to get good spreads, while others néed to be jumped. It seems all barrel/rifling/powder/cartridge combinations have their own preferences.

 

[bricktop]

Some rifles I don't bother trying to find a load with the bullet jammed, because I know under certain common circumstances that a live round will need to be removed from the chamber - mostly hunting rigs.