Pressure high or low.

[new shooter]

Where does pressure go up when having the bullet closer to the lands or say 40 thousand off. I will start loading my new 338 lapua -imp. I want to work up my load to max then play with seating to get the best groups and lowest ES. I will be using r-33 powder 300 gr bergers. I finally got all 300 lapua brass fire formed. That was a learning experience for a old guy. Thanks for info Joe

 

[Barrelnut]

Pressure goes up the closer you get to the lands for the most part. Jamming the bullet into the lands with no jump or free flight movement of the bullet can raise the pressure substantially. BUT ALSO, pressure can start to rise as you seat the bullet deeper into the cartridge case as the bullet displaces space in the cartridge. So, you really need to pay attention to pressure both ways, especially when you start getting to the extremes in either direction.

The above is a reason for the idea of finding your bullets preferred seating depth with a series of medium loads and then using that preferred seating depth to work up your powder load

 

[FearNoWind]

... I will start loading my new 338 lapua -imp. I want to work up my load to max then play with seating to get the best groups and lowest ES....

Bad idea, IMO. Like the man said:

... [find] your bullets preferred seating depth with a series of medium loads and then using that preferred seating depth to work up your powder load

 

[LRSickle]

The above is a reason for the idea of finding your bullets preferred seating depth with a series of medium loads and then using that preferred seating depth to work up your powder load

Yup! I agree. It seems that when I find my bullet's preferred seating depth at a lower charge it stays the same no matter what charge I end up with.

 

[bob4]

It seems that when I find my bullet's preferred seating depth at a lower charge it stays the same no matter what charge I end up with

That"s the norm. The only thing that would change preferred seating depth is using a different bullet/projectile.