finding the lands

[Raythemanroe]

I think taking the ejector out is the way to go.. Repeatable, easy enough and doesn't cost a nickel.. My experience is a couple thousandths can effect the tune so two to three either way isn't getting it done to compete with some of these folks. Just do it the correct way once and the questions get answered themselves..


Ray

 

[Trophy 2000]

Ray, what do you like to start load developing off the lands?

 

[Raythemanroe]

Ray, what do you like to start load developing off the lands?

I think that depends on what I'm loading for and the bullets im using... I do generally start in ten-twelve thousandths and work my way out.. WSM seem to work 9-10 in and this BRA likes 7-8 in..


Ray

 

[Texas10]

Seating exactly to lands is only a starting point, a benchmark of sorts because eventually you'll be adjusting seat depth to find that sweet spot the bullet/barrel likes most. But having an accurate starting point, or benchmark is IMOP important mostly because later on, as the barrel erodes you'll want to make accurate adjustments to seating depth to chase accuracy. It's also important to know exactly where your bullet touches lands because during a seating depth study for accuracy improvement, pressures and velocity jump when the bullet starts out lodged in the lands. Knowing exactly were this occurs helps in deciphering the group measurements and POI shift.

In that regard, the only method I've found that will produce an accurate measurement, and one where this is no question as to where exactly the bullet is in relation to the lands, is to use this method in combination with the Stoney Point or Hornaday OAL gage:

FL size the LNL modified case as you normally would and seat a bullet long. Screw it on the rod and insert it into the chamber with a firm push, then retract. Any tendency to stick is an indication the bullet is in the lands.

Gradually seat the bullet deeper until there is no tendency whatsoever to stick upon retraction. That is your nearest "off the lands" measurement.

You'll have to adjust for the difference between the modified case base to shoulder length compared to your Fire Formed brass. If for instance, your FF brass is .004 longer than the modified case, you'll ADD that to your base measurement to get your distance to lands with your fired brass.

Very experienced hand loaders with years of practice will tell you they use the stoney point or Hornaday tool and get consistent results. But anyone just starting out will have a lot of trouble getting consistent results, particularly with the smaller bullets, and no way of knowing if the measurements they are getting are accurate. The method I've described will allow the user to feel, with a good measure of certainty, exactly when the bullet begins to lodge in the lands.

Those who are using the Hornaday or Stoney Point tool might like to try this method and post your results, along with whether the factory described method or this modified method works better in your gun. I get repeatable and consistent results within .001 using this method, and especially when measuring throat erosion and adjusting seating depth to chase the lands in my 6mmBR.

As always, YMMV.

 

[Trophy 2000]

I just love the science of reloading and the many ways to get the same results. What I most enjoy is the fact so many are willing to share their wealth of knowledge. I thank all that do that, most of all that compete and still share, that is true sportsmanship and what I love about the shooting sports. May you all have a safe and rewarding year 2018.

 

[rhovee]

Sorry if this has already been asked. But does everyone clean the barrel out before finding the lands? I clean before, but noticed that after 20/30 rounds fired I can feel resistance from closing the bolt. My load is ten thou off the lands when barrel is clean.

 

[Trophy 2000]

Never gone that long between cleanings.Very interested in the response to this question from forum members. I'm curious as to what they think the answer is.

 

[Texas10]

Sorry if this has already been asked. But does everyone clean the barrel out before finding the lands? I clean before, but noticed that after 20/30 rounds fired I can feel resistance from closing the bolt. My load is ten thou off the lands when barrel is clean.

Absolutely! Throat/leade must be clean, including removal of any carbon ring if present. Otherwise, your numbers will be worthless.

I make this check often, especially if changing bullets or lots but also to document barrel erosion, but what you describe sounds like a carbon ring buildup. Stiff bolt closure after 20 to 30 rounds sounds worrisome. A thorough investigation with borescope might be in order.

 

[dmoran]

Sorry if this has already been asked. But does everyone clean the barrel out before finding the lands? I clean before, but noticed that after 20/30 rounds fired I can feel resistance from closing the bolt. My load is ten thou off the lands when barrel is clean.

I suggest you identify where your getting the bolt resistance from. While it could be the bullet making contact as your thinking, it also could be some where else, such as the case making contact with chamber fouling or a carbon ring issue. Welcome... and good Luck
Donovan

 

[rhovee]

I cleaned it with bore tech eliminator using wet patches nylon bush and more wet patches. Took my measurement multiple times. When chambering the first round I had to push the bolt forward to close. I took the round out and could see a carbon ring around the ogive. I’ll have to re check lands again.

 

[tenring]

Just couple days ago, I loaded my 6BR brass with 29.5 grs Varget and used Alex method to find kissing the lands. Berger 105 targets. Loaded three each CTBO with first touching, then 005" in and then 010" jam; another three each with .005" jump, finally .010" jump. All shot at 200 with no wind. The .010" jam load produced one hole. Next, I will shoot same load in groups of five.

 

[Tim Singleton]

My absolute farthest from the lands I have every needed to go for accuracy has been between .015 in and .020 off. Most of the time +/- .010". If your keeping your rifle in tune you want to check the throat and adjust seating depth every time you load. The other nice thing about knowing exactly what distance from the lands you are is you can share data with others and it will mean something. Accuracy windows at long range are tiny. Those wide windows at close range do not happen at long range.

Some think this is important enough to remove the barrel and verify touch to a certainty
They are world champion class shooters they don't do it because it's a fun thing to do. It pays

 

[Dusty Stevens]

Im a fan of the running start. In the real world though im kinda like whidden- no matter how far my jam advances im always in it.

 

[JFrank]

Being fairly new to reloading I only have one way that I'm comfortable with, with a clean barrel and chamber I use the Hornday LNL with comparator to find the lands and create my benchmark from CBTO. The interesting thing is that a new box of 107 smk with the same lot numbers, measure the same BBTO , weigh the same BUT when measuring to the lands again .012 difference. Wow
I take my back up box with a different lot number that measure BBTO slightly less hench (back up box) now the CBTO is back to normal. What is up with that?
J

 

[Fotheringill]

May I respectively suggest finding the depth article at the Berger site. Someone here will have the link (at work and cannot poke around) It will give you the best jam or jump for your rifle based upon seating depth and shooting targets. It worked wonderfully for me. I.E. you may thing jamming .01 is best for you, but jumping .04 might really be the cat's meow.

Ah, there it is further up. Method also works for non VLD bullets

link

http://www.bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/

 

[powderbrake]

Being fairly new to reloading I only have one way that I'm comfortable with, with a clean barrel and chamber I use the Hornday LNL with comparator to find the lands and create my benchmark from CBTO. The interesting thing is that a new box of 107 smk with the same lot numbers, measure the same BBTO , weigh the same BUT when measuring to the lands again .012 difference. Wow
I take my back up box with a different lot number that measure BBTO slightly less hench (back up box) now the CBTO is back to normal. What is up with that?
J

I have found that different bullet lot numbers will vary up to .010 on the cartridge base to ogive measurement. I will adjust my CBTO to give me the same location of the ogive into the lands on the rifle for best accuracy.

You will also have to adjust your seating stem for a change in lot numbers..... AND for best accuracy, measure the CBTO on each round after you seat your bullets. The bullet tip length will vary even within a lot.

 

[JFrank]

I have found that different bullet lot numbers will vary up to .010 on the cartridge base to ogive measurement. I will adjust my CBTO to give me the same location of the ogive into the lands on the rifle for best accuracy.

You will also have to adjust your seating stem for a change in lot numbers..... AND for best accuracy, measure the CBTO on each round after you seat your bullets. The bullet tip length will vary even within a lot.

Right on, I was surprised that the same lot number bullets varied that much. Glad I checked as I'm heading to a match this weekend.
My rifle likes a .016 jump so an extra.012 would have been ugly!
J

 

[Dusty Stevens]

Being fairly new to reloading I only have one way that I'm comfortable with, with a clean barrel and chamber I use the Hornday LNL with comparator to find the lands and create my benchmark from CBTO. The interesting thing is that a new box of 107 smk with the same lot numbers, measure the same BBTO , weigh the same BUT when measuring to the lands again .012 difference. Wow
I take my back up box with a different lot number that measure BBTO slightly less hench (back up box) now the CBTO is back to normal. What is up with that?
J

That comparator is not repeatable and lot numbers mean nothing on off the shelf bullets plus youre measuring to a different spot than your seater die hits. If your seater die hit the same exact spot as your comparator tool they would all measure the same.

 

[JFrank]

That comparator is not repeatable and lot numbers mean nothing on off the shelf bullets plus youre measuring to a different spot than your seater die hits. If your seater die hit the same exact spot as your comparator tool they would all measure the same.

Thanks for weighing in Dusty'
My comparator is the only tool I got for this stuff, I use it for BBTO I use it for finding the lands CBTO and I use it to check seating depth. I worked up my load with CBTO at 1.798 to the lands then tested seating depth and ended up at 1.782 .016 jump all good right?
As I said the odd thing the same lot number bullets in the new box were 1.810 to the lands. My back up box is 1.798 to the lands again so at this point I feel I would need to retest the odd box I suppose. Alex made a great point not to start load development until he had enough components to wear it ' anyway Talk to me man
J

 

[Tim Singleton]

I'm just glad I seem to be seeing more posts and questions lately about seating depth
Until it sinks in how important this is your not going to see a lot of improvement in your performances