Initial seating depth test

[luckyshot52]

Thank you. Do you use your normal neck tension when finding your jam point? What do the land marks look like on the bullet? Square or rectangle? Thanks

 

[Tim Singleton]

I use a bushing .003 smaller than a loaded round
The marks depend on the profile of the bullet.

 

[Ned Ludd]

Tim, very clear illustration of the effect and importance of seating depth, I like it. At ~.003" neck tension, how far past "touching" do you estimate your "hard" jam is? I've always heard one might expect hard jam to be anywhere from .015" to as much as .025" past touching, but I have never needed to delve that far in for what I do. If that is true, then I would guess that for all three of those seating depths, the bullets were actually seated into the lands. Do you recall if your chambered bullets engraved at all three of those seating depths? When you use this approach, is there some way besides engraving to know when you have actually moved the bullet out of the lands? I am asking out of curiosity because I typically focus on the jumped side of the lands using a Stoney Point tool to find the approximate CBTO at "touching", and work from there.

 

[Brians356]

Use Erik Cortina's method (in bold on page 1):

http://forum.accurateshooter.com/threads/long-range-load-development-at-100-yards.3814361/
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[Tim Singleton]

Tim, very clear illustration of the effect and importance of seating depth, I like it. At ~.003" neck tension, how far past "touching" do you estimate your "hard" jam is? I've always heard one might expect hard jam to be anywhere from .015" to as much as .025" past touching, but I have never needed to delve that far in for what I do. If that is true, then I would guess that for all three of those seating depths, the bullets were actually seated into the lands. Do you recall if your chambered bullets engraved at all three of those seating depths? When you use this approach, is there some way besides engraving to know when you have actually moved the bullet out of the lands? I am asking out of curiosity because I typically focus on the jumped side of the lands using a Stoney Point tool to find the approximate CBTO at "touching", and work from there.

The bullets I usually shot it's about .025 from jam to just touch