The first rule is there are no rules.

L

lilabner

Guest
Berger recommends seating certain of their bullets touching the lands for best accuracy. Others recommend the same thing with different bullets. I just went through an exercise with my new 6.5 Swede and Hornady bullets seated .01, .02 and .03 from the lands. I also shot groups with the 129 gr. SP interlocks seated right down to Hornady's cannelure. That put them a long way from the lands. However, they grouped as well as the .01s and better than the .02s and .03s. Is this a case of "The first rule is there are no rules" or what? Does it have to do with how an individual barrel vibrates?
 
liabner-I have found that bullets always shoot better loaded atleast touching the lands. I load everything so that it is as long as I can get them without camming the bullets back into the case. You will find that if you take that cartridge combination that shot good short of the rifling and measure the velocity and then load a cartridge combination that is loaded at least touching the rifling but at the same velocity that the combination touching the rifling will shoot the best.
 
What you're finding out...

The main reason that loading close to the lands often improves groups is that it uniforms the initial combustion pattern by negating (to a degree) the effect of varied case neck tension. In other words, if the case necks are not completely equal in how tight they hold the bullet, one cartridge to the next, by loading against the lands you can mitigate this effect and often improve accuracy.

But if your case necks are uniform, loading against the lands isn't necessary. There is absolutely no such thing as a particular bullet design "liking" such and such a jump to the lands, or "liking" to be loaded against the lands. While some bullet makers may say this, get them on the phone and have them explain the science behind what they say. You'll either get an earful of blather, or no answer at all. The distance to the lands thing has simply been a repeated mantra over the years, and most folks--even seasoned competitors--don't really know why they do it.

One other thing that loading close to the lands can help mitigate is the effect of runout, in the event that you have a large degree of runout on your loaded cartridges. Cartridges with a high degree of runout will fair better in many instances if they don't have any jump to the lands, as this will help prevent them from engraving off axis and going down the bore with the tip spiraling. A close seating to the lands may help such bullets align with the bore more gently instead of having them batter into the lands harshly, as they would in the case of a long jump to the lands.

If your handloads are straight (little to no runout) and your case necks are uniform, you don't need to load against the lands to enjoy great performance.:)

Dan
 
Seasoned veterans load with the bullet into the lands because it makes sure the bullet gets started straight as can be going down the rifling. If you have clearance between the neck and chamber wall will allow the bullet to start crooked down the rifling if it is not loaded into the lands.
 
Lilabner: I have been using Berger bullets for quite some time now and have been experiencing excellent accuracy.
I have never heard or read anywhere that Berger recomends certain of their bullets be seated so they touch the leades of the rifling.
Until I read your posting.
I shoot mostly ultra-accurate Varmint Rifles (both factory and custom) and several different Big Game Rifles (both factory and custom).
I am pretty pleased with the accuracy I get but I guess I could always use more!
I double checked my Berger boxes (several types and vintages of them) and found no reference to "touching the lands".
So I went to the Berger Bullets website and read there.
The only reference I could find regarding "recommending seating out to the lands" was this one, which I found in the "VLD bullet" section only: "If you do not achieve the accuracy level you are looking for by jumping a VLD bullet then you may find that your rifle will shoot VLDs more accurately if the bullet touches the rifling when the round is chambered. VLD bullets may need a little more tweaking than non VLDs but when they are working well they are tough to beat".
With many of my factory Rifles this "touching the rifling" is NOT possible!
I have tested for myself over the last 3 decades with this touching the rifling theory and to tell the truth I can do without it.
In other words I get as good as accuracy with small jumps (and sometimes LONG jumps) to the rifling as when touching!
In addition I shoot many of my Rifles when the temperature is high and during mid day.
Both ammo and Rifles sometimes get "warmed up" in my uses and I don't want to have to worry about the combination of hot ammo and any other factors (intentional or not) causing dangerous pressures.
I have equipment that allows me to measure and set my seating depths to within just a couple thousandths of an inch of the rifling - if physically possible - and IF the Rifle shoots best adjusted thusly!
I have several Rifles that shoot best when bullets are jumping in excess of ten thousandths of an inch (in excess of 1/100th of an inch!).
Each Rifle is an individual.
Hold into the wind
VarmintGuy
 
I have to agree with newberry's comment about loading into the lands negating differences in case neck tensions. I shoot a lot of 30 cal. 155 gr. bullets and will comment on those. The Berger VLD's need to be loaded so that they are about .015 into the lands to get the best accuracy. I think this is directly related to the ogive design and I don't know of anyone successfully jumping these bullets. On the other hand most shooters find the best results with the Sierra 155 bullet if they load it with a .020 to .030 jump to the lands. Once again I think this is related to the ogive design. I just finished testing a new Berger 155.5 gr. bullet this past weekend that doesn't seem to matter if it is seated on the lands or jumping .020. Once again it is a different ogive design. This is not to say that a certain ogive design bullet will only shoot one way or the other, it is just information that I have found and have gleaned from others shooting the same weight bullets, but I will say that I believe it is pretty true about the VLD's. I suspect that the Sierras can have loads developed for them that will allow them to work either way. One downside of a hunting load that is loaded into the lands is having to extract the loaded round and leaving the bullet stuck into the rifling and a trigger full of powder.
 
The Berger information I referred to was not on printed material from Berger. It came from the Midway catalog which says the VLD should be seated touching the rifling. Midway says a different bullet, the LTB, is not seating sensitive and will perform well at different depths. My rifle is happy with a deeper seating depth for the Hornady Spire Point and that was good news as I wanted a reliable hunting load.
Some very good shooters had advised me that .02 was generally best for hunting rifles. However, my largest groups were those seated .02 off the rifling. If I'm understanding the good info contributed, the catridges I am producing are apparently "straight" enough that deep seating is causing no major problems. That is also good news!
 
lilabner
clowdis as well as Dan is, but I can take the seated depth one further, if you are to seat the bullets into necks that are of .0005 to .001 neck tension (not for hunting) then seat those bullets .020 longer than the lands, the chamber will seat those bullets for you (if you have a good chamber) and this action takes care of chasing the lands and will remove any TIR peresent.

Clarence
 
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