243 win, IMR 4451, RL 26 velocity results

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Idaho Trecker, Apr 13, 2015.

  1. Idaho Trecker

    Idaho Trecker Well-Known Member

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    Made some range time today and just thought I would put some of my findings out there for these newer powders. I was mostly concerned about finding my max pressure/velocity today and here is what I came up with. These were shot at 200 yards and 15 feet from the chrono (shooting chrony) to muzzle.

    I was running a 24" barrel from a Sako 85 varmint and Vortex Viper HST 6-24.

    I forgot to mention my bore and all bullets were coated with HBN

    105 Hornady BTHP
    RL 26
    46 2952
    47 3058
    48 3117
    49 3212

    The primers looked good through the 49 grains but I had a faint extractor mark on the case head. I think there is room for more speed.
    My downfall is the fact that my rifle has a 1:10 twist and I have not been able to stabilize 105 bthp or A max. I was hopeful that the bthp would stabilize since it doesnt say a 1:9 or faster required.

    on to the 87 V Max and IMR 4451
    43 3086
    44 3177
    45 3272
    46 3299

    At 200 yards the vertical distance from the first shot to second was 1 3/4 inch. From shot 2 to 3 there was 1/8" vertical and horizontal!!! and the last shot was actually another 1/4" lower than shot 2 vertically but 3 1/2 inches right (dont think it was me)

    It looks like the 4451 is going to work great for my setup and with a .4 bc its not terrible for some paper punchin way out there.
     
    Last edited: Apr 13, 2015
  2. westcliffe01

    westcliffe01 Well-Known Member

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    Re: 243 win, IMR 4451, RL 26 Ladder/velocity results

    So if I understand, you loaded 1 bullet with each weight of powder ? What does that tell you ?

    For a ladder test, you try to pre-determine the best seating depth for your bullet, then load 5 each with each powder weight. Then shoot a 5 round group with each set, always using the same point of aim. Then you compare drop relative to point of aim and GROUP SIZE to determine which powder node looks promising. Take along some unrelated loads or factory ammo to get the bore fouled and into a stable condition prior to shooting test loads.

    Something about your reloading data looks fishy. Max loads for the 105gr A max are listed at 2980fps on the Hodgdon reloading website (with 40.4gr of IMR 4451) while your 87gr Vmax loads seem a tad slow (43.8gr of 4451 giving 3342fps from a 24" barrel).

    So somehow you are slow on the light bullet and fast on the heavy one ? And your max load is way over the posted limit for the Vmax ? And you have no group information so you have no idea which load is going to repeat well, regardless of how fast it is ?

    I have been running a calculated 3200fps with a 95gr Berger hunting bullet, but that is with an AI chamber. I certainly would not expect that kind of speed with a 105gr. Be careful, don't get hurt and check if anything groups a ---- near the ragged edge. Sometimes there is a high node that works out, but not all of the time. A very hot load that you develop in spring could cause serious problems in the middle of summer, or if you tweak the seating depth or use a different primer.
     
  3. Idaho Trecker

    Idaho Trecker Well-Known Member

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    Re: 243 win, IMR 4451, RL 26 Ladder/velocity results

    I guess my terminology is off I should have said just looking for max pressure with those powder/bullet combos while finding the least vertical. Once I found the node with the least vertical I will go back and load groups within that range. I'm just trying to put some personal experience out there with the new powders.
     
  4. westcliffe01

    westcliffe01 Well-Known Member

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    Re: 243 win, IMR 4451, RL 26 Ladder/velocity results

    Least vertical drop = maximum velocity. The bullet is going to obey the laws of physics. But all that tells you is the limit of the system. It does not give you any other information regarding accuracy at all. Usually the best approach is to start with a mid weight load and work up and shoot for groups. One should find an accuracy node close to that point and the question is just whether there is another higher up. You discover the same information regarding maximum pressure following the other route, but you will get to the higher pressure end last and can choose not to shoot the highest loads if you start seeing pressure signs earlier. If you develop a hot load in summer, it should be fine at any other time of the year, but beware developing a hot load in spring or winter that you want to shoot year round.
     
  5. Idaho Trecker

    Idaho Trecker Well-Known Member

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    I made that mistake once when I developed a load for 6mmAI and IMR 831 in winter at 30 degrees and touched one off at 85 degrees the next summer... needless to say the primer was blown. I know i'm not near summer temps yet but they are at the max temp (todays data taken at 67 degrees) I will be hunting in since I'm gone from may to October fighting fires and no time to shoot.
     
  6. Ring

    Ring Well-Known Member

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    NEMTHunter likes this.