Learning how to seat to lands

Discussion in 'Reloading' started by midmo, Jun 10, 2015.

  1. midmo

    midmo Well-Known Member

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    I am looking for the easiest and most simple ways to load my ammo to the length of the bullet to be just off the lands. I am pretty new to reloading. I have already gone to the range and tested loads but I am looking to get more accuracy out of my reloads. I have a .30 06 remington 700 with a blind mag. I have heard on the .308's for 700's you just make your col just to fit the magazine because the lands are so far off. Is it this way with .30 06 in these rifles?
     
  2. Rick Richard

    Rick Richard Well-Known Member

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    You can only do so much with a factory mag. I would load to the maximum length of the mag and from there experiment by decreasing the length by .010 - .020 of the cartridge until you achieve optimum accuracy. Now this recommendation is if you want to shoot as a repeater.

    If shooting as a single shot, I would purchase the necessary measuring devices (Hornady) that will measure the cartridge/projectile ogive to the lands and work back from there using the Berger suggested method for VLDs.
     
  3. AZShooter

    AZShooter Well-Known Member

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    You can see where the lands are by seating a bullet long in a dummy round and polishing the bullet jacket with steel wool. If the bullet is out too far you may not be able to close the bolt. Just seat a bit deeper and try again. When the bolt closes the bullet will be engraved by the rifling. Most likely the marks will be long and deep. Seat the bullet deeper, polish with steel wool and repeat. Incrementally seat deeper till the marks on the jacket are barely visible. That will get you close enough to compare the rounds that fit and feed from the magazine box.

    If you have a comparator and a caliper you can measure from the ogive to base of each round and have a fairly close value for the distance to the lands. You can make an expensive comparator by using a large nut and drilling a hole slightly smaller than bullet diameter and chamfering the edge of the hole with a deburring tool.

    See this video to see how the hex comparator is used:

     
    Last edited by a moderator: Sep 8, 2018
  4. Corey Schwanz

    Corey Schwanz Well-Known Member

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    Get yourself a tool like the Hornady OAL gauge or the Sinclair Seating Depth Tool. These will help you establish how far out your rifling actually is. Once you know where the rifling is at, you can start setting up test loads at various distances off the lands. You will likely have to make a choice as to whether you want the bullet out really close or if you want to utilize the magazine capability in the rifle. For MOST factory guns, when the bullet is out long enough to touch the lands or close to, they are usually too long to fit the magazine.
     
  5. Dosh

    Dosh Well-Known Member

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    ^This. I always seat by the ogive, never tip to base. Some bullets can get you closer to lands, the long VLDs not as easily at max mag length. Good luck
     
  6. AZShooter

    AZShooter Well-Known Member

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    Most of us have all the measurement tools but Midmo asked for simple way. He could do it today without going to a gun store IF they even had the right tools.......
     
  7. g0rd0

    g0rd0 Well-Known Member

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    I make a dummy with each of my bullet styles. How I do this is resize a brass then lube the inside of the neck and (WITHOUT POWDER OR A PRIMER), place the bullet of choice in the neck just enough to hold it in place and chamber it. As the bolt closes the bullet will seat as the ogive contacts the rifling. (This dummy is my max oal for that bullet style in that rifle only). Now to start I subtract 30thou to start from there I experiment with different oal's getting closer to the moal.
    For example I have a savage mod.11 in 7rm, 150 grn ETIPS like 15tho from the lands. But, 150 grn sp's like 25 thou off and 175 grn sp's work best on the lands.
    I also have an old Huskavanna 6.5X55 that only likes 160 grn rn 10 thou off the lands and that is the only diet that it will tolerate.
     
  8. AZShooter

    AZShooter Well-Known Member

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    Now if you grab a Berger hybrid you can usually just seat to fit and feed from the magazine and it will most likely shoot. I have loaded for at least 20 rifles in various calibers and those hybrids shoot where you seat them. Incremental powder charge increases has been all that was needed to find a tight group.

    Earlier this week I found a load for a friend's 1968 6mm Rem using the 95 gr classic hybrid. Jump to rifling due to a 2.8" mag box was approx .170". I used the same method I mentioned above to determine the approximate jump.
     
  9. MagnumManiac

    MagnumManiac Well-Known Member

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    To answer your question regarding the 'simple way' to determine the origins of your rifling, these 2 methods are the easiest.
    If you have a cleaning rod, do this, close the bolt in the rifle, put the cleaning rod all way down the barrel from the muzzle end until it touches the bolt face, mark the cleaning rod shaft flush with the muzzle, remove it and the bolt from the rifle. Take the bullet you want to use, hold the rifle muzzle DOWN and drop it in the chamber, using a biro pen or similar, hold the bullet in place, carefully put the cleaning rod into the muzzle until it just touches the bullet tip, mark flush with the muzzle again. The measurement between the 2 marks is the distance to the rifling on the OGIVE of the bullet, it is NOT the COL measurement from base to tip.
    The other method will give you the COL measurement for each bullet style quicker and easier.
    Take an empty case, using a dremel cut off wheel, or a hacksaw, cut 2 slots in the case neck opposite each other, clean any burrs off, size the neck, place a bullet in it and carefully chamber it, once chambered, lift and turn down the bolt a few times, this stops any stickyness of the bullet.
    Carefully remove the round, if the rifle has a plunger ejector, use your thumb to hold it centred as you pull back on the bolt, this will stop it dragging on the chamber walls, completely remove the round and measure from base to tip. Record the measurement, repeat several times to make sure you're getting an accurate measurement.
    Once this is determined, I keep a record of the throat length, this is done by seating a bullet backwards in the above modified case and measuring it, then for each bullet, I keep a dummy round at the length it is to be loaded.
    As long as you set your seater die stem tight, whether you measure by base to tip or base to ogive, the seater plug seats by the ogive. I have never seen a complete box of bullets that have had the same base to tip or base to ogive length, they all differ by a few thou.

    Cheers.
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