Methodology For Determining Best Loads

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  • unshelledpilot

    Sharpshooter
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    Jun 27, 2014
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    Hammond
    Hello All

    The headline is eye-catching, I know.

    I have a question for all the reloaders and statisticians. I'm reloading for several AR pattern rifles. I started reloading with the express intent of bulk, long term, shtf style storage. Now that I'm comfortable with my reloading skill, I wanted to take on a larger project. Having several AR's, I want to develop a load that is PRECISE across all of my rifles. To do this I was thinking of doing the following:

    You can assume that,all else being equal, the only changes that will be made are powder loads.
    1. Work up five loads of 20 rounds each, totaling 100 rounds for each individual rifle being tested.
    2. Shoot each load in each rifle to find the most precise load by grouping.
    3. Average the size of the groups across the range of tested rifles.
    4. Use the averages to develop another set of 5 loads, 20 rounds each.
    5. Rinse, repeat steps 1-4 to perfect a load that will give the best groups across the range of rifles tested.
    6. Use the perfected load to manufacture bulk batches of ammo.

    I must state again that the purpose of this testing is to develop a load that will give the best groups across the range of rifles tested. Then use that load to stock ammo for a rainy day. Does anyone see a flaw in my methodology? Any recommendations to improve or streamline the process? Comments? Critiques?
     

    sloughfoot

    Grandmaster
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    Apr 17, 2008
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    Huntertown, IN
    Yeah. Here is how you streamline it. Put 24.5 grains of Varget, RE-15, 4895, or N140 behind a 69 grain bullet from any manufacturer. Load this ammo in any rifle with a 9, 8, or 7 inch twist. It should be about 2950 fps from a 20 inch barrel. That would be the goal anyway.

    Your focus on group size disregards terminal ballistics. Terminal ballistics can never be ignored. It is all that really matters. Group size is third or fourth down the list of what is important.

    1 minute ammo is just as lethal as 1/2 minute ammo.
     
    Last edited:

    Woobie

    Grandmaster
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    Dec 19, 2014
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    You're not going to realize the full accuracy potential of each individual rifle this way, but I think you realize that. I would be curious what twist rates / barrel lengths you've got. The old 1:12 AR's won't stabilize the heavier bullets, but the newer 1:9 or faster will stabilize most anything. If you have 1:7's or 1:8's you might think about building some sort of MK 262 clone based on a 77 gn bullet.
    I have to agree with sloughfoot on the terminal ballistics point. In SDM school for the Army we were getting hits on steel 4 or 5 shots out of 10 at 600m. That's with a basic off the rack m4 with iron sights and m855 ammo, shooting in the prone. Point being, if you know what you're doing (and you practice), you can hit your target at the far reaches of its ability to perform on the target. I love shooting small groups, but the reality is, if your equipment will shoot 1 1/2 MOA, you'll be hard pressed to shoot that well in a combat or field environment. The .556 isn't exactly the most lethal round in the world, but you can give it some help with good bullet selection.
    I like your thinking, though. I think a compromise can be found with enough reloading, and your methodology looks to me to be the way to get there. Enjoy the journey!
     

    Broom_jm

    Master
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    Dec 10, 2009
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    Depending on how many "several" is, I think you're on a wild goose chase. I can see trying to come up with one load that works well enough in all of your 223/5.56 rifles, but to my way of thinking, it's WAY more fun to have a load that is VERY accurate in a specific rifle. It all boils down to your objectives and what will make you happy. A load that cycles each action and rings a 6" steel target at 100 with any of your rifles is cool, but only if that same load will print well under an inch with at least one of your rifles.
     

    AllenM

    Diamond Collision Inc. Avon.
    Industry Partner
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    Apr 20, 2008
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    Avon
    Sloughfoot knows what he is talking about and offers good advice....However if your like me, I like to tinker and test different things.
    I have always used this method for rifle loads and find it works very well. It's called OCW and here is a link.

    OCW Overview - Dan Newberry's OCW Load Development System

    I like it and it works
    Only problem I have had is watching temperature changes and adjusting my loads for them but once you have you OAL and optimal velocity it is pretty easy to adjust for temperature. I usually have 3 loads for my favorite rifles. winter, summer and fall and spring fall into the same category.. But like i said I like to tinker :) Loads developed in 30 degrees are not as accurate in 80 degrees.
     

    Leo

    Grandmaster
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    Mar 3, 2011
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    Lafayette, IN
    Yeah. Here is how you streamline it. Put 24.5 grains of Varget, RE-15, 4895, or N140 behind a 69 grain bullet from any manufacturer. Load this ammo in any rifle with a 9, 8, or 7 inch twist. It should be about 2950 fps from a 20 inch barrel. That would be the goal anyway.

    Your focus on group size disregards terminal ballistics. Terminal ballistics can never be ignored. It is all that really matters. Group size is third or fourth down the list of what is important.

    1 minute ammo is just as lethal as 1/2 minute ammo.


    +1 standard performance load. I only disagree with the any bullet. I would change to any 68 0r 69 gr MATCH bullet. Those third world no name, cheapies shoot poorly. Put this in the rifle ans spend your time learning to shoot, not at the reloading bench. I wish someone would have told me that when I started. I spent way too much time "developing" loads like a bench jockey and not shooting like a Rifleman.
     

    kludge

    Grandmaster
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    Mar 13, 2008
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    Disregarding the rifle and the shooter, precision ammo has two things - a good bullet and low SD & ES.

    You can get lucky with ammo that has neither... My Savage 110FP shoots 7.62 NATO into ~1MOA.

    To know what your SD & ES are, you need a chronograph... groups at 100 yards might tell you what load a rifle might like, but there's not yet enough drop or wind to tell you what the groups will behave like and longer range ES and SD are a function of the load parameters/ammo consistency. An OCW or 300yd ladder test can help if you don't have a chronograph, but it leans heavily toward which load the rifle likes, and not always toward the one with the lowest SD and ES.

    A good bullet will fly straight. low SD and ES means it will fly consistently. Low ES and SD will translate from rifle to rifle; the specific load usually does not.

    Just as a "for instance" you could have a load with moderate SD that shoots sub MOA in one rifle, that none of the other rifles like. But when you change the load for a low SD/ES load, the group in the one rifle opens up to 1.5MOA, due to resonances, but then all the other rifles get better.
     
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