"how to find your lands exactly"

[fps plus]

Respectfully have to disagree

It doesn't matter what is pushing the cartridge in whether it's a finger , wooden dowel , ejector , extractor ,bolt face once the case shoulder hits the chamber the bullet cannot be pushed any further into the case . I'm talking of using unsized cases from the firearm

[260 Rem]

Originally Posted by fps plus

Respectfully have to disagree

It doesn't matter what is pushing the cartridge in whether it's a finger , wooden dowel , ejector , extractor ,bolt face once the case shoulder hits the chamber the bullet cannot be pushed any further into the case . I'm talking of using unsized cases from the firearm

Correct, I think we may be looking at two different scenarios. In yours, the bullet is very loose in the neck and there is virtually no resistance on the bullet as the case moves forward..allowing it to slide back without getting etched into the lands. If it is not etched into the lands, you should be able to eject it and get the same measurement every time. I can see the need for the epoxy.
I have sometime fitted bullets in a split neck which has low grip, but even then, the bullet sometimes sticks in the lands when the case is ejected because it takes very little resistance for the soft copper to enter the lands. When I use that method, I do repeated measurement cycles to make sure the bullet is not getting pulled out of the case which would give me a false reading.

[Bushrat]

Originally Posted by 260 Rem

I have sometime fitted bullets in a split neck which has low grip, but even then, the bullet sometimes sticks in the lands when the case is ejected because it takes very little resistance for the soft copper to enter the lands. When I use that method, I do repeated measurement cycles to make sure the bullet is not getting pulled out of the case which would give me a false reading.

When doing that I like to color the bullet with a marker, or carbon smoke it with a candle flame, the neck will scrape the ink/smoke on the bullet jacket as it is seated, if the bullet is hanging up in the lands and pulling the bullet out of the case a bit upon extraction it will tell you. May as well also color the ogive as well, it will show the degree of contact it is making with the lands. It will also tell you if your bullet is seated straight in the case, if the land marks made on the bullet are longer on one side of the bullet than the other the bullet isn't seated straight. If the bullet is seated straight and this is happening then the chamber is off center to the bore. This is very common with factory rifles and not all that uncommon with custom jobs either.

[Bushrat]

Re my above reply, make sure the neck opening/case mouth is square. I don't chamfer the inner case neck to seat the bullet when I make cases to find seating depth, if they are chamfered it is hard to tell on the bullet where the scrape begins and ends and could be chamfered down into the case neck quite far so that if there is bullet pull back upon extracting it might not show it.

[DLab]

I ordered the correct tap for doing the modified cases for the Hornady tools , I drilled and tapped two for my .30 br. and two for my buddies .25 Souper from fire formed cases two days ago ,I used Wilson case holders from my trimmer ,clamped it in my drill press vice and threaded the case in this setup also,bit of a learning curve to this point ,sacrificed a few cases{mostly my buddies }.I used a 9/32." drill bit but a 17/64ths.might be better ,pre-drilled both primer holes first with smaller bits ,then those holes helped centre the larger bit.
With datum line on Lapua brass measured at 1.1645"with Berger 115 gr. FBHP and "heavy thumb" pressure to lands gave me a reading of 1.666 multiple times ,just seated lightly touching gave me 1.659".
If the same pressure is used to seat the bullets into the lands each time, you should get the same measurement using the same bullet and case with the Hornady tool.
Just for curiosity sake ,I took the bushing and expander button out of my Redding full length sizer and bumped the shoulder datum to 1.1635 ,the difference to lands, if any, wasn't worth noting .I'll be using this case and bullet for future measurements either way.
Also modified a case{shortened the neck} for using the chamber length gauge insert that Qwert referred to in his post ,use the bolt for this, chamber measured 1.534" for case trim length reference.
This works for me ,not saying it's the best set up, would a lathe be better? absolutely ,but I don't have access to one.I'm thinking the clamps and rod system would be more economical , with decent calipers should work fine.I already had the Hornady comparator sets, tools .
I've tried the split case and pinched neck methods and found them to be inconsistent as far as repeatable measurements go ,I think because of varying bullet jamb depth and trying to remove from the chamber with out moving the bullet in the case neck.
Consistent repeatability is the key ,I think. This is what works for me , YMMV.

[DLab]

I should have added that I've used the method described by .260 Rem. ,it worked well also. I just don't have a Micro adj. top die for the .30 BR . Standard type dies will work with this method but it's a bit more tedious.
The modified case method with the Hornady tools will work regardless of the dies on hand.

[qwert]

A Lee Collet Neck-sizing die and a little ‘trial and error’ partial resizing in the press, can be used to prepare a fire-formed case with the correct neck tension for ‘finding the lands’.

IMHE this is a lot better and easier than using the more common ‘pinch’ or ‘slit’ the neck procedures. The Lee die produces a very concentric neck and will not be distorted by uneven expanding, pinching or slitting.

Good Luck, YMMV.

[Bushrat]

Originally Posted by qwert

A Lee Collet Neck-sizing die and a little ‘trial and error’ partial resizing in the press, can be used to prepare a fire-formed case with the correct neck tension for ‘finding the lands’.

IMHE this is a lot better and easier than using the more common ‘pinch’ or ‘slit’ the neck procedures. The Lee die produces a very concentric neck and will not be distorted by uneven expanding, pinching or slitting.

Good Luck, YMMV.

^^^this^^^

[michaelmicallef]

I use the split neck method but use my finger to push the round in until it stops then I extract the round by pulling it out with a fishing leader I previously threaded through the primer hole. Easy and you can feel if the bullet got stuck
In the lands when you pull on the leader. Which would give you a wrong measurement. You can push the round in slowly to prevent it actually jambing in the lands but rather touch the lands. Works great for me. I use a drummel tool with a cut off shell to split the necks on the brass and then sand the burs off with some sand paper. I measure using a comparator because the same bullets very slightly from one another.

[375HH]

Try a little case lube on the bullet (ogive). Seems to help keep them from sticking in the lands

[Coyotebutcher]

Originally Posted by fps plus

This is my method
Take a round that has been fired from the firearm in question . Do not resize but make sure it still will chamber in the gun . Take a bullet you want to use , put a small dab of 5 minute epoxy on the iNSIDE the case only slide a bullet in question the neck . Barely started into the neck . Carefully insert the case with bullet and epoxy into the chamber and the close the bolt . Let the epoxy cure and remove cartridge . The cartridge has the bullet seated by the land so now you have a sample to measure

If you don't like sticking rounds with epoxy in them into your rifle:


1. Split a resized cases neck on one side
2. Loosely seat desired bullet by hand
3. Chamber round in desired rifle
4. Carefully unchamber the round (do not drop it)
5. Measure COAL

Of course a chamber gauge is much more accurate but doing this method a few times to double check measurement. And using a few bullets from the bath to be reloaded can reduce your margin of error. (With the split neck you should be able to recycle the casing by wiggling the bullet out)

[covey ridge]

Originally Posted by markg

Funny this topic came up today, as I picked up my newly chambered rifle from my smith today. We had this very discussion in his shop. I asked him to make me a once fired case to use in my hornady comparator tool. He told me I didnt need it and he made me a rod with a tool that clamps down so you can measure the difference between the bolt face and when you put a bullet in pushed to the lands. This is his preferred method and he thinks you get a more accurate reading. I argued a bit about it needing to be measure off the lands and he responded with " the bullet is pushed into the land."
He is alot smarter than me about these kinds of things so I decided to take him at his word.

I tried to take a measurement to determine my seating length but I managed to screw it up somehow. (no fault of my smith) I just suck at mechanical stuff. I got a coal reading that is somehow short of the ssami coal so I must be doing something wrong.

I am familiar with the method your smith uses and I think it is sound.

That said, do not immediately assume that you did something wrong. Just a thought, but maybe your rifle was chambered short of ssami specs?

[covey ridge]

Originally Posted by elkhunter11

the method or tooling that you use to find the distance to the lands really doesn't matter, and in fact the actual distance to the lands doesn't matter, as long as the result is that you are able to get your seating die adjusted to provide optimum accuracy with your load in your rifle.

yes

[covey ridge]

Originally Posted by 260 Rem

I should have added in post #22, that if the bullet is tight in the neck, it can easily jamb into the lands by .005 - .010 before the headspace bottoms out on the shoulder. Even with the Hornady tool, it can be a challenge to get repeatable measurements because of differential pressure on the forcing rod.
Mark...you got a pic of the rod/clamp gizmo...sounds like the same principle described by covey?

It does. If you google COL measurement with clean rod you will find several videos and sites that describe this method in its various forms. Western Powder Company has one and Benchrest.com or something similar has one.,
I would post them but I am having system problems.

It was the method that was described in almost all reloading manuals when I started loading and it was the method that bench rest shooters often used and only become less known when the companies like stoney point and hornady started marketing gadgets that we all must have.

With whatever method one uses I agree with Elks point in a previous post.

BTW, taking the extractor out is a Kool idea!

[Johnny G1]

My brother used to put the bullet in the case back wards and slowly push it into the lands and take measurement's from there, but you have to have good caliper's to get it right, me, I just put the bullet in the gun and it has killed every time. lol

[markg]

Originally Posted by covey ridge

I am familiar with the method your smith uses and I think it is sound.

That said, do not immediately assume that you did something wrong. Just a thought, but maybe your rifle was chambered short of ssami specs?

Hmmm maybe?? I might have to have a conversation with him after family day.

[qwert]

Originally Posted by markg

Hmmm maybe?? I might have to have a conversation with him after family day.

Your smith should be able to provide a drawing of the reamer he used to cut your chamber.
I suspect he will be able to provide lots of other guidance.
I suggest you make careful notes.

Goof Luck, YMMV.

[covey ridge]

If one uses new brass, or fired brass, neck sized brass. or full length brass or whatever, do you not finds your lands exactly where the ogive touches the lands?

Is the OAL not the length of a seated bullet that allows the ogive to touch the lands while the cartridge head is square against a closed bolt in the fire postion.

If the bullet is not seated deep enough it will push into the brass or into the throat of the rifle or both.

Does it really matter if this not exactly zero to a millionth of and inch. After all is this not a point where you will start your tweeking and not end your tweeking?

Is it not more important that when you arrive at your sweet spot that you have a way to set your seating die so you can repeat and enjoy the fruits of all your tweeking.?

Seatingis by pushing the ogive? Isn'tit?

Still think that shooting without ejector might help accuracy.