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Thread: H322 and 77 grain Sierra TMKs.

  1. #41
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    Quote Originally Posted by lsllc View Post
    But what does the SD tell you that is useful? It’s irrelevant information. Knowing it doesn’t help your load.


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    I'm sure there are some guys here that know way more about statistics than I, but I'll take a stab at it an explain why I look at SD and rarely at ES during load development.

    Standard Deviation will tell you the likely-hood of a shot's velocity falling within a certain deviation from the mean velocity. The Extreme Spread only gives you the difference between the two outliers in your string. A round that I may have dicked up could be the cause for a high ES, while while a high SD is indicative of a load that will consistently result in a larger vertical divergence at distance.

    For a visual reverence think of a bell curve with steep sides having a low SD (the vast majority of the shots are in the center by the mean).
    The high SD bell curve is one that looks like it got pancaked with a hammer. Yeah, all the shots are still within the same ES, but they're as likely to be on the high and low end as they are in the middle.

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  2. #42
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    I get that. But the ES is telling you about your process. The ES is telling you not only that your load is adequate, but that you aren’t making mistakes in your loading process. Those outliers are misses. The 90% or 95% within your deviation just tells you that the load works. But it’s a poor indicator of when you’re going to miss because of your ammo.

    Much of the time when dudes blame wind, they are under or over the target because they had a round 50 FPS from their average velocity. Their process needs fixed or their components have a problem. But if the guy doesn’t look at ES, and only looks at SD, their SD will indicate there isn’t a problem and it’s just an “outlier”. When the guy works up the load an only runs ten across the chronograph, one or two rounds are “outliers”, what happens when ten or twenty percent of the time 100 rounds they loaded for a match or for hunting turn out to be “outliers”? They MISS. They either drop one into the 7 ring at 600, or miss 2/3 IPSC targets at 800, or they gut shoot an animal.

    If loading for precision, the “outlier” needs to be within 20 FPS, but preferably 10 FPS.


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  3. #43
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    Think of it this way, you can’t have a bad SD with a good ES. But you can have a good SD with a shit ES.


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  4. #44
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    Quote Originally Posted by lsllc View Post
    Think of it this way, you can’t have a bad SD with a good ES. But you can have a good SD with a shit ES.


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    You can have either. You can shoot an even 2" 10-shot group or a .5" 9 shot group with one flier opening to 2".
    They are not the same. ES and SD should both be factored (and 3sigma if youre sick). Yes in the above example root cause analysis needs to happen, but you can see whats possible, and there is an intermittent issue vs normal variation.

    Also - any updates on these loads? Im looking to start loading 223/556. Right now the plan is to replicate the OG markm load.

    Is there a new better go-to or start there?..
    Also, does brass need trimmed each firing? Im coming from pistol loading so trimming and pocket reaming are uncharted territory. Thanks yall.

  5. #45
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    Quote Originally Posted by MegademiC View Post
    Also - any updates on these loads? Im looking to start loading 223/556. Right now the plan is to replicate the OG markm load.

    Is there a new better go-to or start there?..
    Also, does brass need trimmed each firing? Im coming from pistol loading so trimming and pocket reaming are uncharted territory. Thanks yall.
    The problem we've realized is (since starting to load long range/precision whatever ammo) lot changes are huge. I always thought is was benchrest dogma, but the H322 we're shooting now is different than the old stuff.

    I was getting popped primers on some ammo loaded milder than stuff I had success with years before.

    I'd just start at the good old 21.6 and adjust from there. As far as trimming, I use the giraud and trim every time. Doesn't take much off, but it chamfers the case neck.
    "What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v

  6. #46
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    Quote Originally Posted by markm View Post
    The problem we've realized is (since starting to load long range/precision whatever ammo) lot changes are huge. I always thought is was benchrest dogma, but the H322 we're shooting now is different than the old stuff.

    I was getting popped primers on some ammo loaded milder than stuff I had success with years before.

    I'd just start at the good old 21.6 and adjust from there. As far as trimming, I use the giraud and trim every time. Doesn't take much off, but it chamfers the case neck.
    Thanks. Ive been pre-prepping brass waiting for my dies to show up, lol. Cant wait to start.
    Last edited by MegademiC; 02-23-22 at 19:35.

  7. #47
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    Cool. Are you going to anneal or load bulk and skip annealing like I do?
    "What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v

  8. #48
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    SUPER impressed with your velocity on that! Shoots pretty good as well! In my 20"(slow for a 20") could never get above ~2640fps with H322/77's without pressure signs. I do remember right at 22.0gr shot very accurately though.


    Quote Originally Posted by NWPilgrim View Post
    This H322 loaf is interesting but the XBR load I think is one of those rare universal exceptional loads. Seems somewhere between 22.9-23.5 every gun will find a super accurate node. Mine like either 23.0 or 23.2 depending on the rifle. A real classic load for 77 gr bullets. I also shoot the Nosler CC since I can get them cheap in the 1000 ct lot.

    I believe that the xbr load in that range is pretty universal as well, my node is 23.1-23.4gr with a 77gr SMK.
    Last edited by IALoder; 02-26-22 at 08:26.

  9. #49
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    Quote Originally Posted by IALoder View Post
    SUPER impressed with your velocity on that! Shoots pretty good as well! In my 20"(slow for a 20") could never get above ~2640fps with H322/77's without pressure signs. I do remember right at 22.0gr shot very accurately though.




    I believe that the xbr load in that range is pretty universal as well, my node is 23.1-23.4gr with a 77gr SMK.
    I’m at 23.8 gr in mine. Velocity around 2740 fps.


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  10. #50
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    I'm a big fan of the 23.4gr XBR/77gr TMK load.

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