Interesting Load Development Results

Jud96

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The information I’m going to share in this post really made me excited when I discovered it. A few months back, I started testing 215gr Berger Hybrids in my .308 Norma. I used my traditional load development of finding a velocity node and then fine tuning it to get low ES and SDs. Pictures 1, 2, and 3 show charge weights that I shot purely for group size, shape, and point of impact in the past couple weeks. You can see that 70.7 and 70.8 are very tight groups and both hit very close to center. The 70.9 load wasn’t as good but impacted roughly 1/2” from the center of the other two loads. This is what I would call the Optimal Charge Weight. I found these loads without any use of a chronograph. I purely went off group size, shape, and point of impact as I said before. Now let’s go back to that velocity testing I did in the past. In picture 4 you can see my velocities from 70.2 to 70.8 were very tight with an ES of 18 across that span of charge weights. All of the data so far I have shared has been with brand new brass. I then tested the velocities in once fired brass because once fired brass always delivers more velocity grain per grain than virgin brass. As you can see in pictures 5 and 6, I tested 70.0, 69.7, and 69.5 all for velocity. The average velocity for all three loads was 2917 and the ES from the slowest (2902) to fastest velocity (2936) across all three charge weights was 34 FPS. That’s an ES of 34 with charge weights varying 0.5gr of powder! That is a very good node. Now to wrap all of this up, my optimal charge weight was 70.7-70.8gr of powder in virgin brass. Going back to my initial velocity testing, 70.8 did 2916FPS. Looking at my once fired velocity tests, the average of all three combined charge weights was 2917FPS. The OCW method and the velocity node method both landed me on the exact spot. That is some very interesting and conclusive evidence if I do say so myself!

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Mikecr

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I guess I'm missing the conclusion part.
But hopefully it still shoots ok with fully fire formed load development.
 

Jud96

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I guess I'm missing the conclusion part.
But hopefully it still shoots ok with fully fire formed load development.
When I tested for velocity 70.8 grains in virgin brass was the sweet spot. When I tested the OCW method I landed on the same charge weight. I didn’t realize this until I went back and checked my data. The fired brass uses 69.5-70.0gr to get the same speed and I settled on 69.7 as being the load for fired brass because it gives the same speed as 70.8 in virgin brass.
 

Jud96

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I disagree but okay. The OCW method landed me on the same node that also had the velocity flat spot. In virgin brass it took 70.8gr to get in the node. In fired brass 69.5-70.0 was the node as I indicted and showed. So I loaded 69.7 and it was in the middle and it shot this group and had the same average velocity as 70.8gr had in virgin brass, which was also the same load that was the OCW. This evidence shows that two different load development methods led to the same conclusion. I did not run these tests parallel. I tested them months apart and did not realize how they lined up until I laid my data and notes out and could track how they lined up.
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Savage 12BVSS

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Interesting read for sure, I tend to agree with you, they both proved themselves. That also is a good node you find yourself in :)

I'm a firm believer that it doesn't matter how you reach a specific charge weight and distance off lands......when you do it is a final focus of the load.
 

Jud96

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nice groups , the ES is not terrible but ... ehh

maybe dry graphite necks , to better your spread ???

Extreme spread isn’t everything. Erik Cortina shot a 1.3” 5 shot group with his F-Class rifle on camera at 1000 yards and had an ES of 18 for those 5 shots. Yes ES is important, but I have chased small ES and have had much larger and much more finicky loads. What I am showing is a load that consistently hits in the same general point of impact, within 1/2”, but also has a 0.5gr wide flat spot in velocity. If you load in the middle of that like I did at 69.7, you get a group that’s 1/4 MOA and an ES of 24 for 5 shots. This is a magnum cartridge in a hunting rifle. This isn’t a 6BR 20lb bench rifle. The goal is consistency both in velocity and accuracy as well as point of impact across a span of powder charges.
 

DUSTY NOGGIN

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i aint bagging on ya or your abilities .. was just saying its an easy test without adjusting any other part of your load

were dealing in a world of variables .. some days when thing go great the numbers say otherwise .. some day shots go bad and the numbers say they shouldn't ...

we all know eric sucks at shooting and the wind just happened to drop all em right there for him ;)

all that matters we know when our rifles are shooting . when you know , you know
 
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25WSM

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Jud your test show exactly what I teach my customers to do as far as velocity testing. Just looking at the first sheet I concluded that 70.7 would be the load I start with. Then after doing seating depth I would do 70.6 70.7 and 70.8 and see what it liked best. I always take the node and cut the bottom half off and then use the middle of what's left.
70.2
70.4
70.6
70.8
Cut in half leaves the 70.6 and 70.8 and right in the middle of that is the 70.7 I would have started at. This method seems to work almost 100% of the time.
Shep
 

Jud96

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Jud your test show exactly what I teach my customers to do as far as velocity testing. Just looking at the first sheet I concluded that 70.7 would be the load I start with. Then after doing seating depth I would do 70.6 70.7 and 70.8 and see what it liked best. I always take the node and cut the bottom half off and then use the middle of what's left.
70.2
70.4
70.6
70.8
Cut in half leaves the 70.6 and 70.8 and right in the middle of that is the 70.7 I would have started at. This method seems to work almost 100% of the time.
Shep
Exactly what you described is what lined up with my velocity testing and my OCW testing. Again, I ran both forms of load development months apart. The OCW method showed 70.7 and 70.8 shooting very good groups and hitting very close to the same point of impact. My velocity testing also showed 70.7 and 70.8 being a flat spot or node in the velocity. I think it is very conclusive that using multiple methods can lead you in the right direction if done correctly.
 

25WSM

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I found the velocity method is just easier and gets me to the same place faster. I tested it against ladder test and it always seemed to match up pretty well.
Shep
 

Jud96

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I also wanted to go back and see where once fired brass put me as far as velocity and charge weight. So that is why I tested 69.5, 69.7, and 70.0 grains. As you can see 69.7 was right in the middle and proved to have decent ES and shot a 1/4” group. So both the velocity method and OCW method landed me on the same load that shot 1/4” or better and had good velocity spread.
 

Jud96

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I found the velocity method is just easier and gets me to the same place faster. I tested it against ladder test and it always seemed to match up pretty well.
Shep
This was my first time using the OCW method and I have had good luck with the velocity method. I think both obviously work well and if you do them both right I think you’ll end up with very similar end results like I demonstrated here.
 

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