Help with seating depth

Discussion in 'Reloading' started by XILoveGunsX, Oct 15, 2012.

  1. XILoveGunsX

    XILoveGunsX Member

    Messages:
    24
    Joined:
    Aug 31, 2010
    I bought some 185 Berger HVLDs for my 300 WM this weekend because I've really been wanting to try some out. Its a Rem 700 5r stainless milspec 26" tube. I've been shooting 220SMKs with around .75 moa but I want to try something a little lighter and flatter for hunting. I've read the sticky on seating depths for the vld but I don't have a tool to measure for OAL. I've been loading at 3.340 for everything else and have had good luck. I'm wondering where I should now start as far as COAL for the VLDs. Or should I just wait until I can get my hands on an OAL tool.

    I've only been reloading since this summer and I really enjoy it. I started with a 44mag and then my 308 then -06 and now my 300. Any advice will be greatly appreciated.

    I've got some RL22 & H1000 and CCI 250s to go with it. Starting load would help too as I don't have a manual for the Berger bullets

    Thanks in advance
    Tucker
     
  2. handloader1

    handloader1 Active Member

    Messages:
    41
    Joined:
    Sep 22, 2012
    Pick up a OAL tool. Good luck.
     

  3. baldhunter

    baldhunter Well-Known Member

    Messages:
    446
    Joined:
    Jun 18, 2008
    Tech note from Berger on seating depth
    The text below is from the Berger website on how they recommend finding the correct seating depth for their bullets

    ---------------------------------------------------------
    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.

    Note: When discussing jam and jump I am referring to the distance from the area of the bearing surface that engages the rifling and the rifling itself. There are many products that allow you to measure these critical dimensions. Some are better than others. I won’t be going into the methods of measuring jam and jump. If you are not familiar with this aspect of reloading it is critically important that you understand this concept before you attempt this test.

    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).

    Trying to find the COAL that puts you in the sweet spot by moving .002 to .010 will take so long the barrel may be worn out by the time you sort it out if you don’t give up first. Since the sweet spot is .030 to .040 wide we recommend that you conduct the following test to find your rifles VLD sweet spot.

    Load 24 rounds at the following COAL if you are a target competition shooter who does not worry about jamming a bullet:
    1. .010 into (touching) the lands (jam) 6 rounds
    2. .040 off the lands (jump) 6 rounds
    3. .080 off the lands (jump) 6 rounds
    4. .120 off the lands (jump) 6 rounds

    Load 24 rounds at the following COAL if you are a hunter (pulling a bullet out of the case with your rifling while in the field can be a hunt ending event which must be avoided) or a competition shooter who worries about pulling a bullet during a match:
    1. .010 off the lands (jump) 6 rounds
    2. .050 off the lands (jump) 6 rounds
    3. .090 off the lands (jump) 6 rounds
    4. .130 off the lands (jump) 6 rounds

    Shoot 2 (separate) 3 shot groups in fair conditions to see how they group. The remarkable reality of this test is that one of these 4 COALs will outperform the other three by a considerable margin. Once you know which one of these 4 COAL shoots best then you can tweak the COAL +/- .002 or .005. Taking the time to set this test up will pay off when you find that your rifle is capable of shooting the VLD bullets very well (even at 100 yards).

    [​IMG]
     
  4. FEENIX

    FEENIX Well-Known Member

    Messages:
    9,806
    Joined:
    Dec 20, 2008
    Yes! There are others but I use Hornady LNL overall length gauge ($30) and modified case ($5, you can also make your own if you have the proper tap/die).

    Good luck!
     
  5. benchracer

    benchracer Well-Known Member

    Messages:
    1,364
    Joined:
    Dec 18, 2009
    You can get by without the OAL gauge or the modified cases. Here's how:

    1. Install and close your bolt.

    2. Using a jag with the tip ground flat, push a one piece cleaning rod into the muzzle of your rifle until it contacts the bolt face.

    3. Mark your cleaning rod at the muzzle (I wrap my cleaning rod in masking tape and score the masking tape with a razor blade held against the muzzle).

    4. Using a length of wood dowel, push your chosen bullet into the chamber of your rifle.

    5. While holding the dowel/bullet in place, gently push your cleaning rod w/flat tipped jag into the barrel until it stops against the bullet you are holding in the chamber.

    6. Mark your cleaning rod again.

    7. After removing the bullet from the chamber and the cleaning rod from the barrel, measure the distance between the marks with your reloading caliper.

    The resulting measurement will tell you the necessary OAL, measured from cartridge base to bullet tip, to reach the rifling. From there, you can perform the seating depth tests recommended by Berger and described above.
     
  6. jbroadnax

    jbroadnax Well-Known Member

    Messages:
    208
    Joined:
    Jan 11, 2006
    I have had good luck using this method. Load one bullet way to long. Force the round to chamber. Remove the cartridge and measure the obl or oal then seat the bullet .02 to .025 deeper. This should have it just kissing the lans. You then then go out or in to fine tune.
     
  7. Lefty7mmstw

    Lefty7mmstw Well-Known Member

    Messages:
    4,280
    Joined:
    May 13, 2012
    +1

    I do similar but use a ss rifle rod and a superfine sharpie for marking. Thanks Benchracer, you saved me some typing.:D
     
  8. SBruce

    SBruce Well-Known Member

    Messages:
    1,786
    Joined:
    Oct 31, 2009
    There's more than one way to skin a cat and this one calls out all the knives.

    First of all, the optimum OAL with your bullet in your rifle with your load is subjective. NOT Absolute. Meaning we have to experiment and find the best combination for our individual circumstance and component selection.

    OAL tools and comparators and precision mics are great tools, but not absolutely necessary to find the best OAL..........there's that absolute word again.:)

    Those tools will sure help us reload ammo at a later date with different bullet lots to the same specs though.

    We can:

    Soot the bullet or mark the bullet with sharpie and seat deeper until barely noticable rifling marks show from chambering a previously fired dummy cartridge/case.......when satisfied, measure the OAL and call that "Jam".

    Split the neck of a previously fired case and chamber the dummy round. measure just as above.....accomplishes the same thing but the bullet will move in/out of the case easier.

    Barely resize the neck of a fired case (just enough to resist bullet movement by finger pressure) chamber and measure.......again, just like before, and easier than splitting a perfectly good case neck.

    Using a once fired/fully neck sized case, seat the bullet deeper and deeper (gradually) untill you just, I mean just faintly see rifling marks (polishing bullet with fine steel wool each attempt obviously)........at whatever seating depth you only faintly see marks, measure and call that "Jam".

    Get a comparator, OAL tool, precision mic, use the cleaning rod method or any of the above methods and you'll get to the same place.........just use the same method every time you do it if you want repeatable results.

    Start at point X and proceed to point Z; somewhere along the way, we'll find the optimum seating depth for that bullet/powder and charge/primer combo in that particular rifle.

    Just remember, after a few hundred rounds fired; that relationship will change due to throat erosion of the lands. Then we gotta re-figure and adjust accordingly. This is obviously where the tools come in, cause we gotta measure and record all that again as the throat changes.....and again, and again, and again.........chase the lands, because they like to run from us.:)
     
  9. XILoveGunsX

    XILoveGunsX Member

    Messages:
    24
    Joined:
    Aug 31, 2010
    Thanks for all the great advice. Ill likely be trying one of those methods over the weekend. Ill pick up an OAL tool as soon as I can after that. How much jam should I account for using one or any of those methods?
     
  10. SBruce

    SBruce Well-Known Member

    Messages:
    1,786
    Joined:
    Oct 31, 2009
    Lots of folks start load development with OAL just barely kissin the lands or .010-.020" back off them. Some guns wont let us seat bullets out that far due to magazine size. Each rifle will genrally require a different "setting".
     
  11. XILoveGunsX

    XILoveGunsX Member

    Messages:
    24
    Joined:
    Aug 31, 2010
    When I push a round into the lands during this process should I assume that I'm. 010, .020 etc INTO the lands? How much should I compensate for to get the bullet. 010 ish OFF the lands
     
  12. SBruce

    SBruce Well-Known Member

    Messages:
    1,786
    Joined:
    Oct 31, 2009
    If you're seeing definitive riflling marks on the bullet, then I'd say that's .020 jam. But again it's relative, so you can call it whatever you want and use that as your baseline. From there, back off .015 and back off again another .015 and once more another .015.......shoot all 4 lengths and stick with what the gun likes after that.

    If you're using one of the fired case and real bullet methods, dont fully FL size the case. Just size enough to grip the bullet or use a neck size only die. Fully FL sizing will sometimes give a false measurement because the ejector plunger will push the case further into the chamber. Generally, a case that's been fired once works best. It shouldn't be tight and wont be loose either.
     
  13. XILoveGunsX

    XILoveGunsX Member

    Messages:
    24
    Joined:
    Aug 31, 2010
    Just what I was looking for thanks!
     
  14. XILoveGunsX

    XILoveGunsX Member

    Messages:
    24
    Joined:
    Aug 31, 2010
    Should I do this before or after an OCW test?