HELP WITH SATERLEE VELOCITY TEST

NW Hunter

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I am working up a new load for my 6.5x284 norma.
I did a coarse bullet seating test of a Lapua Scenar 139 gr at the minimum charge weight of 48.5 gr H4831SC with 140 grain bullets from my Berger manual.
The winner was .025" off the lands.
The following pictures should tell the story of how this test went using a Magnetospeed.
Berger's first edition manual says max load is 51.1 grains of H4831SC. So, I thought I would load up to 54.5 grains thinking I would surely hit max in my rifle before then. Well, I never did hit max.
The case pictured is the 54.5 grain load.
After checking Berger's website, I see they list 53.7 grains as the max for H4831SC with 140 gr bullets.
Is there a second edition Berger manual out with new maxs? I'm not sure why the difference in max loads.
Well, back to my original question.....
From the results on the target, good speed nodes don't show good accuracy.
Should I reshoot good velocity nodes or good accuracy nodes?
In my mind, I know speed nodes are important for long range work.
Conditions were mild and the barrel was never hot to the touch before each shot.
Where would you go from here?
I am also going to continue up the powder charge until I find max in my rifle.
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jd5521

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If your getting bolt click your brass isn’t sized correctly near the base. May need a small base die to correct that. Or it may be that’s what happening to your brass right after firing which would be a pressure issue. If find out which one it is first. If it’s the former I would resize and checks to make sure the brass is fitting correctly in the chamber and then test again. If it’s the latter I would back off my charge and shoot test again.
 

NW Hunter

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If your getting bolt click your brass isn’t sized correctly near the base. May need a small base die to correct that. Or it may be that’s what happening to your brass right after firing which would be a pressure issue. If find out which one it is first. If it’s the former I would resize and checks to make sure the brass is fitting correctly in the chamber and then test again. If it’s the latter I would back off my charge and shoot test again.
I believe it's the latter.
You see any nodes in the test jd5521?
 

jd5521

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never mind I see it. I’ll look more tomorrow for you.
 

NW Hunter

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I dont see any pressure signs on the brass. I thought the Satterlee method looked for nodes by finding flat spots in velocity as powder was increased in .2 gr increments
Seabeekin,
That is exactly right.
I am using the method Scott Saterlee devised and shared on the 6.5 guys utube channel.
I will continue with this method.
 

jd5521

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NW you need to take this out to at least 300 yards of not 500 to really see where this may be heading. You have two decent flat spots in your 100 yard test but that can change at distance which is what you are aiming for.
 

asd9055

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Texas
At the risk of siring the post again...there are several variations of the Satterlee Ladder test.
1. Shooting at the same target over 300 yards looking for point of impact.
2. Shooting through chrono looking for little change in muzzle velocities.
3. A combination of the two.
Also few others out there.
There are many articles and references here for the first method.

IMHO, if you have access to 300 yard range, then the combination is the way to go. But when it comes down to it,
Do What Works For You!

Good shooting!!!
ASD
 

entoptics

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Jan 16, 2018
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I've simulated a OCW/Satterlee/Ladder test in the graph below. I used Excel to randomly generate a velocity within the normal distribution one would expect with a muzzle velocity standard deviation of 10 fps. To get the velocity at each charge weight, I took the OP's data and regressed a line through it, which came out to a slope of 55 fps per grain of powder. I then used the OP's 0.2 grain charge increment to calculate the nominal velocity at each increment, applied the random variation, and ran the simulation 4 times.

I circled all the "nodes" for emphasis...

So...see if you can pick out the OP's data from the randomly generated data...

Find the Node.jpg



If it's not clear, OCW/Ladder/Satterlee etc are usually an exercise in interpreting random noise (seeing faces in clouds or reading tea leaves). It's plausible that they may have some merit for the absolutely most precise ammunition and rifles, or perhaps if one were to fire 10 shots at each charge weight to achieve reasonable statistics.
 

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