Seating depth and pressure

[Tuby27]

I’m a little confused if someone would clarify. When people say seating the projectile deeper, do they mean in the case or closer to the lands? And which will cause more pressure, I would assume a projectile seated deeper in a case would cause higher pressure due to less burning space. So of my picture below of my 270win with Barnes LRX. Which one would have higher pressure signs, left or right?

second question, I may be using the Hornady OAL gauge incorrectly but what I measured my tikka t3x superlite with it showed my lands at about 2.698”. When I use a sized/split neck case and bullet and pushed in and locked with my bolt, it comes up at about 2.827”. Which should I trust? In the picture, the right is my rigged case shown at 2.777” (0.050” off the lands using the sized split neck case)

anyone’s reloaded 270win LRX look like the longer one, with the projectile groove shown?

thanks.

 

[918v]

1. No
2. Don’t close the bolt on a slit case.

 

[Dthomas3523]

Seated deeper = less capacity = more pressure.However, it’s not usually substantial.

Seating into the lands can be a substantial increase in pressure depending.

 

[spife7980]

It’s really pistol loading where the seating depth can cause crazy spikes in pressure, but you’re working with very different proportions of powder, space, mass and momentum. There are no hard and fast rules in reloading other than be safe.

For a rifle, worry about the bullet to land relationship. If you start low powder and work your way up to a safe load any further increase pressure due to deeper seating depth won’t be concerning.