Can someone please define....

[25792SP]

...what the term "bullet seating into the lands" means?

I've been reloading long enough to understand the basics, however, I've always wondered what constitutes "into the lands/rifling".

With a particular bullet that I am currently experimenting, I've been advised to "seat into the lands"....ok....what exactly does that mean?

- Obviously contacting the lands? (bullet almost sticks when round is not fired and ejected from the chamber)

- Somewhat touching the lands? (Rifling is making obvious marks on the ogive)

- Lightly touching the lands? (Very slight marks are being left by the rifling)

All of the above three seating depths are "into the lands" yet all three are very different....or....would the differences between these three seatings not constitute enough variation to effect accuracy anyway?

Interested in some technical details!!!

 

[kiwi3006]

From what I've seen most people go about 0.015" into the lands, some might go as deep as 0.020 but I haven't heard of too many that would go deeper than that.
All of your descriptions are "into the lands" but if people can they specify the depth, of the three the middle one is probably most representative.
If you bullet is a berger read the sticky at the top of this forum to find the ideal seating depth.

Stu.

 

[boomtube]

It's really a subjective thing, without a specific definition. Going in 15 thou is as good a def. as any.

You don't say what you're shooting but if it's a factory rifle and normal ammo, I REALLY doubt that will provide best accuracy.

 

[johnnyk]

25792SP,
It can be somewhat confusing cause everyone seems to have a different name for doing the same thing. I'll try to help by explaining it as I see and use it.
First of all I get the OAL for a particular bullet in my rifle. Say it's 2.7265". I use the Hornady L-N-L OAL guage/w modified case and a bullet comparator that fits on my digital caliber.
Now with 2.7265" as my "starting point", I know that this is just "kissing" the lands and grooves (LaG). If I decide to back the bullet off the LaG .010", which is what I usually do, I initially just set my bullet seating die to seat the bullet longer than desired and start adjusting it down(in) from there until I get to 2.7165" which is .010 shorter than my original OAL.
If I want to seat the bullet .010" "into" the LaG (longer OAL) I set the die to stop at 2.7365". I have done this before but am not sure how exact it is. By that I mean at some point, whether it's .010, .020 or .030 or somewhere in between, the bullet is going to reach it maximum length as dictated by the rifling and start seating deeper in the case, or so it would seem to me.
Anyway, I usually seat 98% of mine .010" off the LaG. I hope this helps. JohnnyK.

 

[lever-hed]

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its important you understand that seating the bullet into the rifling will cause pressure spikes, use a chrony, be safe.