How do I find the lands?

[jeffwhip]

Yes, I am measuring dummy rounds with no primer.

 

[Darcey]

I use the Hornday lock and load overall gauge to find max overall bullet length and buy a Hornday bullet comparator (which measures the ogive of bullet instead of to tip) . Measure The dummy round from oal length gauge and that length will be touching the lands. Now seat your bullet .010" shorter ,or whatever length you are wanting to be off the lands. Very accurate and simple way. I have tried many different ways and found this to be most simple and accurate.

 

[7 loader]

I use the Hornday lock and load overall gauge to find max overall bullet length and buy a Hornday bullet comparator (which measures the ogive of bullet instead of to tip) . Measure The dummy round from oal length gauge and that length will be touching the lands. Now seat your bullet .010" shorter ,or whatever length you are wanting to be off the lands. Very accurate and simple way. I have tried many different ways and found this to be most simple and accurate.

Has worked well for me also.

 

[Jinx-)]

I take fired brass and I necksize it, then I take chopstick and wrap sandpaper around it, then I polish inside of the neck until the point when I can push bullet in with some force applied, getting bullet out usually requires bullet puller, anyway with bullet selected I insert it in the prepared brass, then I chamber it, then remove it and measure seating depth using bullet comparator. When I'm setting up bullet seating die I use same piece of brass with the same bullet to get desired jump.

 

[Mikecr]

Well luckily accurate determination of max oal really doesn't matter(or atleast half of us would be screwed). All that matters is that we find the BEST seating depth, and reproduce it.
This, even without knowing resultant distance to lands.

 

[80Maro]

Well luckily accurate determination of max oal really doesn't matter(or atleast half of us would be screwed). All that matters is that we find the BEST seating depth, and reproduce it.
This, even without knowing resultant distance to lands.

+1 gun)

 

[woods]

If you are going to use the Hornady OAL gauge, it is best if you take one of your fire formed cases and drill and tap it to fit the gauge. Or you can use a Headspace gauge to determine the headspace on the modified case and add that into your calculations to get ACTUAL jump to the lands.

The good thing is that even if you don't do this, your jump to the lands will actually be longer than you think and it will not create an increased pressure situation.

 

[ken snyder]

If your measurement choice does not include a closed bolt and a fireformed case, a yard stick will be all that is necessary. I use dye on a dummy load and look for witness marks and if that isn't contact nothing is. If you have not stuffed cartridges before, get first hand instruction because measuring eroded lands is a judgement call and the difference between stuffed and I shouldn't have done that is small.

 

[OKIE2]

this works but two significant issues here the way it was explained.

1. this method does not measure where it touches. it measures the "jam" into the lands which is about .-040-.050 into the lands. does not it is a bad technique, you just need to remember where you are actually starting from, which is way into the lands.

2. You need a comparator to measure the ogive of the loaded bullet, and not the cartridge OAL. That can vary as much as .017 between bullets in the same box depending on that particular lot.

there are several technical articles on the reloading part of sinclair internationals website, giving very detailed instructions using several tools that they sell that work quite well.

BH

A case with a split neck will not jam a bullet into the lands.
so where do you get it does .040 or .050 ???

 

[Mikecr]

OKIE2, you can get it with a very accurate measure of 'touching', then noting the differences between that and split neck seating.

I haven't checked it directly, but I've noticed with soft seating and 1thou tension unmodified, it doesn't take much effort to jam a varying amount before bullets actually seat further. Of course this is dependent on ogive/leade combinations. But I could picture that with enough split neck tension to keep a bullet from pulling with case extraction, it could push into the lands a bit.

This could be a contributor to many ending up averaging their numbers..

 

[OKIE2]

I have been doing it my way for years with no problem.
I have also blacked the bullet with black marker to see if it is
pushing bullet into the lands and it has never yet.

 

[ken snyder]

It is not possible to make contact without makeing contact. It is also not possible to make contact without transfering. The major diameter of a bullet can not magically go through a smaller land diameter without leaving marks and neither can the major diameter receive marks from something it has not touched. .040 - .050 is an error. It is a very simple Idea, 2 objects can not share the same space, something has to give. With eroded lands that are difficult to find, we do not have a measurement we are supplying an opinion. Absolutely you will find .040 -.050 skid marks all the way down to the mouth if that is how far the bullet is pushed pass the major diameter. Black felt pen is useful in the field but harder and thinner dyes that are available at any machine tooling supply store is preferable.

 

[Mikecr]

But split neck soft seating doesn't work out so precisely for everyone.
If you smoke em, seat em, and the marks indicate no jam, then it sounds like 'touching' to me.
If you end up with varying length/width marking, then the split neck approach is producing less than precise results. This happens, desired or not.

I don't see a challenge to our natural universe with the discussion so far.

 

[rscott5028]

Well luckily accurate determination of max oal really doesn't matter(or atleast half of us would be screwed). All that matters is that we find the BEST seating depth, and reproduce it.
This, even without knowing resultant distance to lands.

Amen!!!

...never mind the fact that there is variability within any given box and/or LOT of bullets.

... plus the fact that your throat is erroding at some given rate