in or out of the lands

Discussion in 'Reloading' started by deadend, Jun 11, 2009.

  1. deadend

    deadend Active Member

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    I read an article recently and the guy said the first thing you should when determining what what load and bullet a particular rifle likes is to pick a recomended bullet and the accuracy load. then load up a bunch of those bullets with that powder charge 5 each set at different depths. Start at maybe 30 thouants out of the lands at two thousandths intervals and go all the way to maybe 2thousandths into the lands watching for excess pressures. So far it made since to me until he said that when you find what your rifle likes as far as being in or out of the lands. then when you start loadin for best bullet and powder load all bullets that distance in or out of the lands the get the best group for that particular rifle. wouldnt different bullets and powder charges and even different primers or brass be maybe creating different preasures. Im relitively new at this and dont want to get my head blown off. HELP PLEASE
     
  2. woods

    woods Well-Known Member

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    Not the way I do it. First of all a lot of factory rifles are limited by magazine length and you have to load to fit the mag. Second is that the powder charge you chose may not yield the velocity you want and you will be looking for the most accurate load by seating depth at a lower or higher velocity than you want. Third is that a difference in type of powder or powder charge can make much more difference than seating depth
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    So for me I look for the most accurate powder with the bullet I want to shoot and find a good combo. Then I might check out some different seating depths.

    But, varying the seating depth by .002" is not a good idea. Starting at .030" off is not bad, but if you only vary by .002" then you would have to shoot appox 150 SHOTS!! No good. Also the ogive curve of the bullets themselves can vary more than .002" from the tip to the ogive. Also it is almost impossible to seat all your bullets to that consistant a depth unless you had perfect inside neck diameters, neck thicknesses and brass softness.

    Varying by .010" will yield much more distinctive results and give you clearer results. And I would go away from the lands from .030" not toward the lands. I have found that seating close to the lands can yield wildly variable results so I either seat into the lands or >.030" off.

    YMMV
     

  3. brassprep

    brassprep Guest

    The answer to your question is YES. Different primers, brass,bullets and lots thereof do create different pressure/pressure curves. Any other answer is wrong. As is the seating depth. Bullets seated by the "jam" seating method often shoot best (see many bench rest articles), however when seating against the lands, the chamber pressure will rise when compared to the same load seated off the lands, but the curve will change and may give a lower pressure at a given point along the bullet travel, ie gas port. The best way to develop a load is to use safe data, for example sierra manual, they will state the oal, the brass, the primer, and the bullet. do not exceed the max load listed-you do this and you will not "blow your head off". If you want to try to seat on the lands for your given rifle, start with the minimum listed load and work up slowly. Remember if you are using the "jam" method, and must unload your weapon, the bullet may lodge in the chamber and powder will spill from the case-seen it happen many times. Even if you get the "best" load in this manner, it may not be the best hunting load, or other purpose load, where un-loading without firing may be required.
     
  4. bigngreen

    bigngreen Well-Known Member

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    I'm just learning how to find the best loading for rifles also and I found the Berger article at the top of this forum helpful. I basically did what was suggested in the article but I went on lands, -.010, -.020, -.030, -.060. I found that the groups tightened up around -.010 so I loaded -.010, -.015, -.020. I got a .380 group out with the -.015.
    I have played with 4 different bullets and all are best @ -.015.
    I don't know if there is an exact method that is the best, but this worked for me with finding the best length to seat the bullet at, that being said I have the magazine length to seat anywhere I need to and I have stayed away from jamming bullets into the lands because of pulling the bullet out of the case senerio.
    I am going to give the ladder test a try for finding the right load. I am really interested in the recent threads about this. Go slow and have fun.
     
  5. justgoto

    justgoto Well-Known Member

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    That is what I was going to suggest

    The Article
     
  6. Gene

    Gene Well-Known Member

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    All the above suggestions are very good. However, I prefer to find a bullet, primer, and powder load from the manuals and start with an OAL that will fit the magazine or is at least .030" off the lands. Start with a powder charge near middle of the load table, load three of each moving up 3 grains in each case, stopping just below the maximum listed. Choose the best group/load from those targets. Change just one item with each step. Now that you have a good load, think about the OAL. How do you know when the bullet touches the lands? There are several methods. You can buy an OAL comparater like the Hornady, I use the Davidson (sold by Sinclair) nose and base set with my caliper. The bullet tip will not touch the lands. These tools show you where the fat part of the bullet (ogive) touches. Shine a bullet up with 0000 steel wool, Seat this bullet out nearly to the manual suggested OAL in an empty case. Insert in the chamber and extract it, look at bullet with a magnifing glass. You should see several marks made by contact with the lands. If none, it means your Oal is too short and the bullet needs to be seated longer. Pull the bullet, shine it again and repeat this process increasing by .010" each time. When you can see the engraving from the lands, back off seating at least .030" load three at that length and three more .005" longer, then three more another .005" longer, etc, until you have about six three shot loads to test. Head to the range, repeat testing at 100 yds, and select the best group. Changing OAL slightly can significantly improve group size. Do not jam bullets into the lands in a hunting rifle, even if they will fit into the magazine. When you unload the rifle, the bullet can remain in the lands, and you will be headed to your shop or the gunsmith to remove every single powder kernel. Good shootin, Gene
     
  7. britz

    britz Well-Known Member

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    Some bullets are going to be more touchy about seating depth than others. There are two kinds of ogive's that bullets have... Tangent and Secant. Most hunting bullets are tangent ogive such as Nosler Accubonds, balistic tips... Some like the Hornady A-max and the Berger VLD hunting bullets are Secant ogive meaning that the shape of the bullet is more streamlined and yield a higher ballistic coefficient. The Secant Ogive bullets will preform much better if they are seated in their "slot" which may be a few thousandths wide and with .03 or so of your rifleing. There is a great "sticky" from Berger bullets on the site that describes how to load test Berger VLD's. the guys from Berger wrote it up.

    Playing with seating depth will yield a more accurate load with virtually every rifle bullet combination, but some will shoot better with a little jump, AKA freebore.
     
  8. deadend

    deadend Active Member

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    Gene and Britz.I THINK I GOT IT!!!. Thank you very much, i will do that as soon as I can locate the bullet I want to try and get to my handloading bench.