finding the lands

[Richard Coody]

Do we really need to find the lands to the .001 of an inch or do we really just need a datum to start our seating test from. i know many have an unreasonable fear of jaming bullets but on my target rifles i always start load development jammed .010 or .020. That distance to the lands is a moving target anyway.

i use the stoney point and after years of practice can get consistent measurements easily to .002 or .003. My thoughts are that is plenty good for a starting point. I find that with a new barrel after 100 or 200 rounds with a well broken in throat that measurement is quite different and than it settles down.

 

[mikecr]

IMO, the only thing needed is the CBTO fully tested as best.
I don't see how land relationship of it matters.

 

[Shynloco]

..... i know many have an unreasonable fear of jaming bullets but on my target rifles i always start load development jammed .010 or .020.

Respectfully, it has nothing to do with a fear of anything when we start testing a load. But it strikes me that if you start with a jam, you are automatically removing your ability to fine tune a load AND you are driving up the pressure of the load you are testing which gives you a false read on the powder itself. I always look to see where the lands just touch the rifling and then back out .010 and start my test and then move in toward the lands .002 and then again another .002 to see how my groups looks. Those groups are BTW three shot groups until I'm seeing a smaller grouping and then fire 5 shot groups for final tuning. Of course if the groups still look like a shotgun pattern after three groups, time to change powder and try something else. But I believe starting OFF the lands is the way to go and is what has worked for me for years. That because not all rifles like the jam and starting off with a bad groups (using a powder or loads other have had success with) leaves you wondering WTF. Been there, done that!

Alex

 

[Papa Charlie]

I would have to agree with Shynloco, loading to jam a round will produce excessive pressures and you really don't know where you are starting from. It is very easy to jam a round into the lands, what you don't know is how far it has gone in and that will vary as bullets vary.
I have always read and been told to start 0.010" to 0.015" OTL. Once you have a powder charge worked up, then you begin to adjust the distance in 0.002" increments both closing the gap and widening as you never really know where the marriage will between bullet and gun.
I also follow this up by revisiting my powder load in 0.2gr adjustments after finding the seating depth to refine the load.
The comment about the throat changing after 100-200 rounds is very much true and will continue to change but not as drastically as the initial break-in. Therefore, it I believe it is import to periodically measure our throats and potentially adjust our loads to match the changing conditions in order to hold the accuracy.

 

[.22gongzilla]

For me, consistency is accuracy. I used to simply let the lands seat the bullet, but IMO even very consistent brass has variances in neck tension that can affect the distance into the lands that the bullet seats, and this is a choke point where pressure ramps up exponentially as the bullet is moved forward. Lately I've been experimenting with seating just off the lands (.002"-.003") instead. Truly jamming would probably be just as consistent, but as a practical matter I need to be able to remove an unspent cartridge at the range during a cease-fire so I've given up on the idea of jamming.

 

[dcali]

You just need a datum to start from, and to know approximately where the lands are so you know if you're jumping or jamming. I find the lands by very slightly jamming a bullet (through trial and error), and noting the CBTO. From that datum, I proceed to seating depth tests (+.005, 0.000, -.005, etc). Recheck as necessary.

 

[dmoran]

Ever notice your load (or someone else's) accuracy may fall off a bit. Lack of keeping the seating depth up with the barrel/throat advancement is what I typically find to be the reason. Continuous measuring for my "touch" point, prevails for me in staying on top of my seating depths, and is the significant reason why its actual spot on relationship to my comparator matters.

 

[Richard Coody]

Respectfully, it has nothing to do with a fear of anything when we start testing a load. But it strikes me that if you start with a jam, you are automatically removing your ability to fine tune a load AND you are driving up the pressure of the load you are testing which gives you a false read on the powder itself. I always look to see where the lands just touch the rifling and then back out .010 and start my test and then move in toward the lands .002 and then again another .002 to see how my groups looks. Those groups are BTW three shot groups until I'm seeing a smaller grouping and then fire 5 shot groups for final tuning. Of course if the groups still look like a shotgun pattern after three groups, time to change powder and try something else. But I believe starting OFF the lands is the way to go and is what has worked for me for years. That because not all rifles like the jam and starting off with a bad groups (using a powder or loads other have had success with) leaves you wondering WTF. Been there, done that!

Alex

to each his own

but when one of our premium bullet manufacturers recommends starting jammed .010 into the lands there must be something to it.
http://www.bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/

personally in my experience the pressure increase between jump and jam isn't that great. Of course i really don't run on the ragged edge of max.loads. more interested in the accuracy node.

 

[Papa Charlie]

to each his own

but when one of our premium bullet manufacturers recommends starting jammed .010 into the lands there must be something to it.
http://www.bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/

personally in my experience the pressure increase between jump and jam isn't that great. Of course i really don't run on the ragged edge of max.loads. more interested in the accuracy node.

Actually Berger does not make that recommendation. They say that many people have used that method with success while others have not had the same outcome.

If you read further into the section title "Solution", Berger states the following:

"The following has been verified by numerous shooters in many rifles using bullets of different calibers and weights. It is consistent for all VLD bullets. What has been discovered is that VLD bullets shoot best when loaded to a COAL that puts the bullet in a “sweet spot”. This sweet spot is a band .030 to .040 wide and is located anywhere between jamming the bullets into the lands and .150 jump off the lands."

They go on to state:

"Many reloaders feel (and I tend to agree) that meaningful COAL adjustments are .002 to .005. Every once in a while I might adjust the COAL by .010 but this seems like I am moving the bullet the length of a football field. The only way a shooter will be able to benefit from this situation is to let go of this opinion that more than .010 change is too much (me included)."

I think that the opening paragraph in this article may be misleading and should have been reworded to be more clear as to the point they were trying to make.

 

[Richard Coody]

Actually Berger does not make that recommendation. They say that many people have used that method with success while others have not had the same outcome.

If you read further into the section title "Solution", Berger states the following:

"The following has been verified by numerous shooters in many rifles using bullets of different calibers and weights. It is consistent for all VLD bullets. What has been discovered is that VLD bullets shoot best when loaded to a COAL that puts the bullet in a “sweet spot”. This sweet spot is a band .030 to .040 wide and is located anywhere between jamming the bullets into the lands and .150 jump off the lands."

They go on to state:

"Many reloaders feel (and I tend to agree) that meaningful COAL adjustments are .002 to .005. Every once in a while I might adjust the COAL by .010 but this seems like I am moving the bullet the length of a football field. The only way a shooter will be able to benefit from this situation is to let go of this opinion that more than .010 change is too much (me included)."

I think that the opening paragraph in this article may be misleading and should have been reworded to be more clear as to the point they were trying to make.

i guess you and i will just have to agree to disagree on the interpretation of this article

 

[Shynloco]

i guess you and i will just have to agree to disagree on the interpretation of this article

Richard,
We may disagree about what Eric's article suggests, but even he specifies that his article discusses Berger VLD's and doesn't promote his method for all bullets. That assumption by some could lead to issues some may not have considered.

Alex

 

[K22]

I seat all my reloads at least .010" or more off lands and never found it necessary to 'jam' the bullet into the land to acheive excellent accuracy. I also make sure I have enough of the bullet seated into the case for adequate bullet tension using approx one bullet diameter minimum seating into case. This has always worked for me.

A cheap, simple and effective tool to measure max COL is the Frankfort Arsenal tool (show in Midway catalog). It's so simple I made my own using two nylon spacers, drilled and tapped for nylon screws. Used with a standard cleaning rod is all you need to measure max COL. If you look at the tool in the catalog it should be obvious how this device works and you can make your own or buy one, they're cheap but work.

Several years ago Sierra published an article on seating depth stating that some rifle / bullet combo's do better seated well off the lands. A good place to begin is .020" and test. I personally would never jam a bullet into the lands because of potential pressure concerns.

 

[Alex Wheeler]

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.

 

[Ledd Slinger]

to each his own

but when one of our premium bullet manufacturers recommends starting jammed .010 into the lands there must be something to it.
http://www.bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/

personally in my experience the pressure increase between jump and jam isn't that great. Of course i really don't run on the ragged edge of max.loads. more interested in the accuracy node.

I've heard that John Whidden has had success with using .001" neck tension, seating the bullet a little long, and allowing the lands to seat the bullet deeper when the round is chambered. It makes sense at first if jam is where you like to be. Problem I see is once a lands starts to wear (since it will not wear perfectly even), I think that this jamming method would cause even greater issues with getting or keeping a rifle in tune. Really no true reference to the lands for information on where your rifle likes to be tuned. Even if you were to jam seat a round with .001" neck tension then eject and measure, I wouldn't trust that measurement as a reference to anything.

The other problem with jamming is that even if you find the lands, then seat the bullet out .010" further, I wouldn't rely on that bullet jamming the same distance in the lands every time, especially if using light neck tension. Like others have stated, this may not make a difference at shorter ranges. Stretch the bullet out to 1K+ and I'm sure the inconsistencies will start to become quite apparent. If I only ever shot 300 yards and under, I wouldn't worry much about any of this

 

[Richard Coody]

I've heard that John Whidden has had success with using .001" neck tension, seating the bullet a little long, and allowing the lands to seat the bullet deeper when the round is chambered. It makes sense at first if jam is where you like to be. Problem I see is once a lands starts to wear (since it will not wear perfectly even), I think that this jamming method would cause even greater issues with getting or keeping a rifle in tune. Really no true reference to the lands for information on where your rifle likes to be tuned. Even if you were to jam seat a round with .001" neck tension then eject and measure, I wouldn't trust that measurement as a reference to anything.

The other problem with jamming is that even if you find the lands, then seat the bullet out .010" further, I wouldn't rely on that bullet jamming the same distance in the lands every time, especially if using light neck tension. Like others have stated, this may not make a difference at shorter ranges. Stretch the bullet out to 1K+ and I'm sure the inconsistencies will start to become quite apparent. If I only ever shot 300 yards and under, I wouldn't worry much about any of this

lots of things work if done correctly. To each his own. John Whidden's record speaks for itself.

 

[Ledd Slinger]

lots of things work if done correctly. To each his own. John Whidden's record speaks for itself.

Definitely some truth in that. I suppose that with a rifle tuned to jam in a healthy and evenly worn lands, this method would avoid ever having to 'chase' the lands and perhaps allow the rifle to stay in tune for extended round counts. It would definitely be worth testing to see if a good tune could be found and maintained with a light jam. Granted every rifle is different, but I do agree that John's records and championship wins do speak of the effectiveness of the jam method.

 

[fredo]

Richard, I also usually start all load development @ jam, +

After determining pressure threshold, then, back off -.010" from contact. Going from jam to jump during load development allows another buffer of safety from a pressure spike...

A wise man told me, if you're gonna jam, then jam! If you're gonna jump, then jump! IMHO, .010" allows enough distance to insure that you're one way, or the other. If a load shoots .010 off, it'll prolly shoot @ .020" off, too.
I don't shoot BR, so not concerned with chasing the last nth' of group size. I'm of the opinion of a rifle is built well, and load is developed with care, pretty much anything is gonna shoot very well with a couple thou jump...

If a load goes to $hit with only a ~.005" seating depth change, that ain't the kinda cartridge I wanna be messin' with, anyway. When shooting 'hotrods', chasing a tiny OAL window become a chore unto itself. I agree with Berger's opinion that ya should be able to enjoy a .030-040" window of happiness before messin' with re-tuning jump length...

Obviously, for the BR guys who 'soft seat' with little/no neck tension, this is a moot point.

 

[stifffingers]

Richard, I also usually start all load development @ jam, +

After determining pressure threshold, then, back off -.010" from contact. Going from jam to jump during load development allows another buffer of safety from a pressure spike...

A wise man told me, if you're gonna jam, then jam! If you're gonna jump, then jump! IMHO, .010" allows enough distance to insure that you're one way, or the other. If a load shoots .010 off, it'll prolly shoot @ .020" off, too.
I don't shoot BR, so not concerned with chasing the last nth' of group size. I'm of the opinion of a rifle is built well, and load is developed with care, pretty much anything is gonna shoot very well with a couple thou jump...

If a load goes to $hit with only a ~.005" seating depth change, that ain't the kinda cartridge I wanna be messin' with, anyway. When shooting 'hotrods', chasing a tiny OAL window become a chore unto itself. I agree with Berger's opinion that ya should be able to enjoy a .030-040" window of happiness before messin' with re-tuning jump length...

Obviously, for the BR guys who 'soft seat' with little/no neck tension, this is a moot point.

Personally I don't care if my bullets are jammed or jumped or where touch is. Where does the gun shoot best. I just jam the bullet I'm testing, remove it, measure it, seat it again 4thou deeper, run it through the action a few times to make sure it doesn't stick in the barrel, then load up 50 rounds at this depth. Then with arbor press, comparator,& seating die I go to the range and test seating depth .003 at a time until I get two bullet holes touching. Then I start seating in .002 increments and three shot groups to fine tune the depth. Of coarse this is all done with a fairly proven load of powder that you know works. The powder ladder test to tweak the load is you next trip to the range.

 

[Trophy 2000]

Enjoyed the opinions on loading relative to the lands. Finding the lands is a science of its own .

 

[6MMsteve]

my 260ai likes .050 jump with various bullets. powders. charges I must have a jumpin hummer