Savage 12LRP, 260 REM load fine tuning

Discussion in 'Reloading' started by freeflight, Mar 8, 2013.

  1. freeflight

    freeflight Active Member

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    Hi there,

    When breaking in the barrel, I found a load with NCC 140gr, 451.gr H4831SC, sub 0.5MOA, 2716 fps, STD 9 fps, ES 22 fps. But NCC 140gr has a lower BC than I like. My goal is have a load for one thousand yard or further. So I continued to search for a high BC, high velocity, low ES load.

    I started with A-max 140gr 0.01" off the land, H4831SC, 210M, new Remington brass. The best load I found so far is 46.8gr H4831SC, compressed powder. 5 shots group is about 0.563-0.627MOA. Velocity 2833fps, STD 14fps, ES 37 fps. There is definitely room for improvement.

    What bothers me most is first three shots usually group about 0.2MOA, the next two shots open the group up. I would also like to reduce the ES. They are fired in about 2 minutes. There isn't much room in the case to increase the charge.

    Any suggestion to fine tune the load is appreciated.

    Thanks,
    Kevin
     
  2. Sargesniper

    Sargesniper Well-Known Member

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    Kevin, you may want to try H-4350 as it may be better for velocity although you dont have to have a lot of velocity to get you to 1000 yds. It may even give you at least or better accuracy. The 130 gr. bullets will also get the job done at that range. If your group opens up as you say you may look at tweaking the bedding screws some. Start out with 40 in. lbs. on all three. Also make sure the rear tang is free floated as well as the barrel after the third shot. It could be as simple as that. If the barrel is touching anywhere, the shot will go off in the opposite direction of the pressure point. ( left pressure, right bullet strike). If you change components,change only one at a time. ( process of elimination). Hope this helps. ..... SEMPER FI!
     

  3. Engineering101

    Engineering101 Well-Known Member

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    I have that same rifle. There is a barrel timing node for 140 gr bullets right around 2,700 fps and they shoot great there. The first thing I would do is assess the barrel timing of your other loads and tweak them to be on a node. That typically eliminates flyers and cuts group size in half. For the theory behind this, check out Chris Long’s website and his OBT paper.

    http://www.the-long-family.com/
     
  4. freeflight

    freeflight Active Member

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    H4350 is the go to poweder for 260, but all I have are Varget and H4831SC. I haven't touch the action screws yet, hoping I don't have to. Will definitely check the barrel after three shots. Thanks.
     
  5. freeflight

    freeflight Active Member

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    Thanks for the link and information about timing node. I never heard about such thing, will study it. I will use the excel sheet or search online for the higher velocity nodes.

    I was thinking about change COAL to 0.02" or 0.005" to tune the load.
     
  6. Sargesniper

    Sargesniper Well-Known Member

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    Have not tried VARGET as of yet. So many powders to play with, i have not tried all of them as i haven't had my .260 very long. I can tell you this though. If you try to gain 6.5x284 velocity(and you can),your barrel wont last long. I had a 6.5x284 that went south in only 750 rounds. It too was a Savage F-Class 30" BBL. I rebarreled to the .260 with a 30" Bartlein Heavy 1-8.5" twist. I have gotten on one load with a 140 gr. bullet up to 2950 but do not want to push it that fast. A 140 gr. at 2750-2800 is plenty fast enough for 1000 yds. if you get the accuracy from it. Good luck and shoot bug holes. ..... SEMPER FI!
     
  7. freeflight

    freeflight Active Member

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    Right, I would be happy with 2750 to 2800 fps, but I just haven't found any accurate load in that range.
     
  8. SAVAGE22-243AI

    SAVAGE22-243AI Well-Known Member

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    4831 SC with a magnum primer worked for me. I also had great luck with the 123 A-Max for a 1580 yd Prairie Dog kill in WY last year. I know it just doesn't "BC" out, but the 140 A-Max and 142 SMK just stayed in the air too long and ended up drifting way of target in a 4-5 mph wind at that distance.
    At 1000-1200 yds my 140 A-Max and 142 SMK were great.

    Using a Savage target action, Walther 28" barrel .260 Rem match chamber 1-8 twist.

    In my rifle the 142 SMK, 140 JLK's and 123 A-Max worked out the best.
     
  9. freeflight

    freeflight Active Member

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    wow, that is a long shot. I know it might not work for me, but still curious to know your A-max 140gr load.
     
  10. SAVAGE22-243AI

    SAVAGE22-243AI Well-Known Member

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    I started with 44 grs of H 4831 SC, and worked up to maximum load, then back off. Start with above and work up 1/2 gr at a time to you max.
    I ended up with 46.3 but this won't work in your gun without testing first.
    My 123 A-Max I ended up with 47.2 gr H 4831 SC, again work up before trying in your gun.

    Does your barrel have standard throat or long throat for 140 gr bullets? This can cause pressure issues if it is short chambered for lighter bullets.
     
  11. freeflight

    freeflight Active Member

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    Thanks. I think it has long throat for the long 140r bullets. My COAL is 2.256" off ogive, which is 0.01" off the land.

    I played with several COAL (0.005" and 0.015 off land) for my 46.8gr load, didn't get any improvement.
     
  12. SAVAGE22-243AI

    SAVAGE22-243AI Well-Known Member

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    Are you using Magnum primers? I use the CCI 250, back off one grain with mag primer and try that. Also seat bullet long and push into rifling on a couple. Your group should touch each other or one hole at 100 yds. If not check your twist in barrel with tight patch on cleaning rod and count twist.
    If it won't group, go to different powder. I also used Varget, and Reloader 22.
     
  13. freeflight

    freeflight Active Member

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    I was using LRP 210M, could try 215M next time. I normally have 3 shot in 0.2MOA, next two opens the group up to 0.5MOA.
     
  14. SAVAGE22-243AI

    SAVAGE22-243AI Well-Known Member

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    Shoot 3 shot groups only, then move to new target for another 3 shot group.