working a load, adjusting COAL

Discussion in 'Reloading' started by Bigeclipse, Jul 30, 2014.

  1. Bigeclipse

    Bigeclipse Well-Known Member

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    Hey all. I have been working a load for my 3006. Right now I have been loading bullets .050 off the lands. I shot 4 loads (different powder charges same bullet seating depth). 2 of which shot OK (~1MOA) for what I am looking for. Next I will be taking the higher charge of the two good loads and try messing with the bullet depth. How small should my adjustments be. Again now my group is right at about 1MOA. I dont really require much better than this but want to see if this rifle can do better. So do I try say .055 and .045 off lands next...or do I try .060 and .040 next? What increments do you suggest. Again this is not a load for distances further than 400 yards nor is it a load for competition. This is a light weight backpack rifle I would like to simply try and improve on the load a bit. Thanks for any advice.
     
  2. Azprc

    Azprc Well-Known Member

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    .020-.030 is normally what I do in steps once I find the OCW.
     

  3. Unofficial Gun Addict (UGA)

    Unofficial Gun Addict (UGA) Well-Known Member

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    Hey Big E... You'll probably find that you are going to get a lot of different opinions on this one. One of the main factors which will influence the answers will have to do with the bullet you are using. I just started loading VLDs and the recommendation was to do seating depth... And then powder charges. Seating depths I used were .020, .040, .080, & .120. I found that both .040 & .080 gave me good results, and since I plan to use these rounds in the field, I opted for .080 so that I would have more bearing surface contact.

    I personally would try a few seating depths (based off others recommendations for your particular bullet)... Pick your best.... And then tweak your powder charges for that depth. You might be surprised with your results.

    Post your bullet as others may be able to speak directly to their experiences with it.

    Good luck!

    Boss
     
  4. Azprc

    Azprc Well-Known Member

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    How does .080 jump lead to more bearing surface contact? We can only assume that you mean contact with the neck, but that means nothing for accuracy.
     
  5. Azprc

    Azprc Well-Known Member

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    I should have clarified, it means nothing for accuracy unless you have very little contact with the neck. Highly unlikely in an 06.
     
  6. Unofficial Gun Addict (UGA)

    Unofficial Gun Addict (UGA) Well-Known Member

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    Correct... More bearing surface contacts the neck which does nothing for accuracy, but I find that more bearing surface of the bullet held in place by the neck tends to hold the bullet in place better when being rattled around out in the field. And .080 is giving me fine accuracy... .040 as well... So I pursued .080. If it weren't for my heart beating like a drum on my last shot... my last test with .080 would have been pretty respectable for 200 yds.



    image.jpg
     
  7. Bigeclipse

    Bigeclipse Well-Known Member

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    The bullet I am using is a Barnes ttsx 168 grain.

    Not sure what any of this means but this rifle will be carried in the field...so if you guys mean the bullet staying seated properly (the deeper the seating the more surface of bullet touching neck) then that might mean a lot for me? These bullets have the weird ring grooves on the sides which allows for even less contact with the case neck. To be exact my bullets at the moment are seated just up to the second groove so if you look at a picture of the bullet you will see that not much of the bullet is seated. If you dont include the boattail (only include the surface of the bullet that will touch case neck) id say about .3inches of bullet is touching the case neck
     
  8. Azprc

    Azprc Well-Known Member

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    Drive bands wont really hurt neck tension. Neck tension means more than how much bullet bearing surface. With the ogive of that bullet you will not have a problem with the neck. When you actually figure out where you are gonna leave it, let us know.
     
  9. FearNoWind

    FearNoWind Well-Known Member

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    I've read that before but, based on my own experience, there is no known hard data to support the theory of this being the better process. I've always found that a primary goal of establishing an optimal MV accompanied by reasonable accuracy without excessive pressures was the way to go. Then I look at seating depth and, if necessary, fine tuning the powder charge as the last finicky detail. If I start with seating depth and things get too close to the lands the powder charge I might seek for the higher velocity may not allow me to remain within safe pressure limits.
    My new loads start at .020 off the lands. When I've accomplished the primary goals I work at .006 increments closer (.014) and further away (.026) from the lands in search of indicators of progress on the target. When I determine which seating length direction holds the greater promise I work in 002 increments in that region to fine tune to my < .5 - MOA standard.
    That's it.
     
  10. Bigeclipse

    Bigeclipse Well-Known Member

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    thanks for the input. I am going to try seating at .040 and .060 off the lands next.
     
  11. FearNoWind

    FearNoWind Well-Known Member

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    Have you read the Berger Tech. Bulletins on seating depths?
    If not, be sure to do that before you start the process.
     
  12. Unofficial Gun Addict (UGA)

    Unofficial Gun Addict (UGA) Well-Known Member

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    That might be something I'll look into next time I attempt to find a good load for a different weight in the VLDs... However, the process worked pretty good this time so I'm not going to complain. I found the sweetspot for the lands in 24 rounds and in about another 20 rounds... I had the powder and velocity dialed in. It was hard to choose between .040 & .080 initially, but I'm glad I went with .080. Increases pressure in the case so I increase velocity a little bit, and it's holding .60" at 200 yds in 5 shots... along with my crap flyer for the 6th, which was 1.44" @ 200. Overall, I'm pleased. Was going to test out to 600 this evening but the wind snuck in and shut that plan down just as I was packing up to go. Maybe tomorrow.

    Oh... And I guess it's all about what a person wants out of their rifle and bullets. I would have been good with .75" @ 100. It will fulfill my needs, but 5 @ .30 and 1 @ .72 is gravy.
     
  13. Bigeclipse

    Bigeclipse Well-Known Member

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    Is this technique also being used for other brand bullets or just Berger? Also, I am a little confused, I had originally thought pressure goes up as you approach the lands...I forgot how I came to this knowledge but I thought as you seat the bullet "longer"/closer to the lands then the pressure goes up. Thank you for posting this as I had things backwards...
     
  14. FearNoWind

    FearNoWind Well-Known Member

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    It's easier to understand, IMO, if you look at seating affecting pressure as a two way street. One direction (seating the bullet deeper) decreases the amount of space between the bullet and the powder (causing less room for expansion upon ignition) to the pressure in the case increases proportionately (althouth not necessary linearly) as the bullet is seated deeper. If you seat too close to the lands you create a "plugged barrel" affect which increases total chamber pressures. The key is to find a bullet seating depth that allows a safe pressure to build with a given powder charge.