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Old 08-13-2019, 05:41 AM
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I just watched and interesting article video on OCW (Optimum Charge Weight) and it seems like an excellent way to determine what your best load is. This method from what I understand determines the point your bullets leaves the muzzle when your barrel is the most stable. The harmonic shock in the barrel reverberates back and forth from chamber to muzzle. When the barrel is most stable is when this shock wave is at the chamber. It may not be the tightest group but it will be the most stable. How to proceed with this test (http://optimalchargeweight.embarqspa...ons/4529817134) A simple explanation video of OCW (
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Old 08-13-2019, 09:43 AM
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The ShootingUK video has a lot of flaws in how he executed and how he analyzed the results from what he claims is an OCW test. Really terrible example video.

He’s not far enough away, for starters. So many guys bend this to be shot at 100yrds, but it really needs to be done at 300 or farther. The intent in the Newberry’s method is to give the bullet enough room to start dropping significantly enough such we can tell what the bullet is really doing, not just what the scope and shooter are doing. Doing this workup at 100yrds is largely a fool’s errand - especially if you’re shooting 1-1.5” groups.

He’s throwing out flyers as “pulled shots,” but his group sizes may not really reflect those flyers as anomalous shooter errors. His group sizes are as big as his dispersions, which undermines the integrity of the methodology.

Then he focuses upon POI close to the bull vs. relative horizontal shifting. Locality to the bull is absolutely irrelevant, and the method is not designed to be analyzed based on horizontal dispersion between groups. It’s the vertical dispersion between one group to the next which matters. His two groups impacting left of center have the same vertical position as the ones centered over the bull, and given 4 clicks of the dial, the result is exactly opposite. He has 3 groups to the left, 2 at 1” left, one at half inch, and then an inch wide group which spans from a bit left of center to a bit right of center, and 2 groups at center. 4 clicks on the scope, and the results would be completely opposite, so those results are a null set - false conclusion by equipment bias, and nothing to do with the load itself. He thinks the rifle is zeroed with another load, liked seeing the groups on center, and ignored the fact there’s no science to anything he did. He’s defining “stability” as close to center on the target. That is NOT Newberry’s method.

He ignores the shape of his groups, and claims he has “stable” loads for a group which has only about 1/4” of vertical and a full inch of horizontal (in a test where he’s focusing upon horizontal), and then says another load is “stable” when it has 1/4” of horizontal, and 3/4” vertical. By Newberry’s direction, those group shapes matter, significantly.

The only thing he got right is that OCW doesn’t concern itself with group size.

Like Chris Long’s OBT, Satterlee’s Velocity curve, or Audette’s Ladder methods, Newberry’s OCW is really an opportunity to determine barrel harmonics. Some followers might believe it has to do with the shock wave being at the chamber instead of the muzzle (which isn’t really supported by wave harmonic theory), Positive Compensation theory would suggest it’s when the barrel constriction/dilation wave is closed at the muzzle. Other philosophizers might suggest the node is found when the muzzle is whipped to either end of its span, meaning it has a zero velocity, whereas the antinode is the position where the muzzle whip has the greatest velocity, effectively in the center of its motion (making it most sensitive to bullet velocity and dwell time). For me personally, despite degrees in engineering and physics, I don’t really care. Knowing my milliseconds of barrel time isn’t pertinent. I just want to know when I throw a charge, it’ll produce a consistent release of the bullet at a consistent velocity, so I know I will get a consistent POI at range.

To that end, these 4 methods work. But what the video described wasn’t an apt description of the method, nor a permutation of said which has merit.

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Old 08-13-2019, 10:57 AM
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Here’s a thread from ~3 years ago where we reviewed OCW theory applied to another member’s targets.

HNI Thread: Interpreting OCW results

It’s the relative vertical position change (or lack thereof, rather) between adjacent groups which makes the method, not horizontal.
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Old 08-13-2019, 04:06 PM
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Nomercy. I like the way you plotted that out. And it makes a good deal of sense. I too don't think it should be shot at 100 yards. I would prefer a minimum of 200. with, like you said 300 even better.

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Old 08-13-2019, 04:17 PM
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Originally Posted by bronko22000 View Post
The way I understand OCW is that regardless of group size you want the group that is more centered around your point of aim.
This is incorrect.

OCW method recognizes that trying POI to POA is simply a matter of dialing on the scope. So the fact the group you identified in the thread I linked is close to POA is irrelevant - add 4 clicks to the scope turret and your theory is destroyed and the result of the analysis changes - because group 3 wouldn’t be “on target” any more, and other groups would be.

That’s not the correct methodology. If you follow OCW method correctly, it won’t ever matter where the scope is dialed or where the POI of any single group hits. It’s all about where groups fall relative to their neighbors. The POA is only an opportunity to ensure the groups are all appropriately relative for one another.

However, I describe in that thread how to analyze the groups according to OCW principles. What you are looking at is the relative position of each adjacent group. Note the yellow curve I overlaid on the edited photo - it’s exceptionally unstable from one group to the next around group #3. Whereas the line is nearly flat between groups #5 - #7.

What that means - considering the inherent variability of charge weights, neck tensions, bullet weights, and case capacities, and under changing environmental conditions, load 3 will fall apart at range, while load 6 will hit very close to the same POI.

OCW method does not care about group size, nor about independent group point of impact. The entire array is what matters.
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Old 08-13-2019, 05:34 PM
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This yellow line is what matters. The multiple POA’s only serve to allow the red line to be established as a reference, then the relative “volatility” of the yellow line is what is important.
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Old 08-13-2019, 06:30 PM
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OK, so now, if I understand this correctly, the left to right movement of the group center is immaterial. We're only concerned about the vertical position of the group in reference to the POA?
But now my question is why do some rifles exhibit impact substantial left to right movement in addition to above and below POA as charge weight changes.
I'm trying to understand this and get as much info as possible. I have a 6.5 CM on the way in the form of a Begara b-14 HMR. I want to get a load developed to shoot out to about 600 or 700 yards.

Trying to watch these videos after reading Newberry's method its hard to believe that so many guys are hung up on group size! As soon as I hear them say that that is their node I have to turn them off.

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Old 08-13-2019, 08:06 PM
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Load development based on small 100yrd groups wins 100/200yrd benchrest matches. Load development which focuses upon consistency in velocity and bullet POI at range is what wins precision rifle matches, F-class, and 600/1000yrd BR matches. Why? Well, because large spreads in velocity and harmonic position will not show up at 100-200yrds, but certainly will present themselves as vertical in 1,000yrd groups. 50fps spread in muzzle velocity elicits 10” of extra, unresolved vertical at 1000yrds, whereas it only introduces 0.1” of unresolved vertical dispersion in a 100yrd group. You’ll easily notice 10” of extra vertical in a 1,000yrd group - not many guys will honestly be able to pin down an extra 0.1” in vertical in a 100yrd group.

As for horizontal stringing in groups - to be honest, I’m well-bedded rifles, with a good cheekweld, fired from a front rest and bag, or bipod and bag, I don’t see horizontal shifts with the same bullet, simply by changing charge weights.

In the last three years, I have started using the Satterlee method, with an OCW twist. I need SOMETHING to shoot at, so I put up an OCW type array, and shoot my velocity curves three fold, shooting round robin groups on different POA’s. I do this at an indoor range, just to get velocities, so I break Newberry’s convention that it should be done at 300+. Here’s a target from one of my node confirmation tests this summer - every .2gr from 41.0 to 42.4. The offset from center is caused by the Magnetospeed V3 hanging from the suppressor - note, there’s about 3/8” of vertical shift in the groups, maybe anomalous, but only maybe an 1/8” in horizontal centroid location.


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Old 08-14-2019, 05:03 AM
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So I think what you're looking for in this test, the way you did it, is to look for groups which had the smallest spread in velocity within that group and a pair of groups that exhibited the smallest difference in velocity?

Sorry for picking your brain. But this is very interesting and I'm sure a lot of other members are checking it out too. In all my years of reloading I was content with my method of load development. Its just been in the past month or so that I've been doing a ton of research on different techniques. What I was doing in the past was good for 100-200 yards because that's all I ever shot. Now that I want to get into long range shooting my method, to put it mildly, 'sucked"! Some rifles I got lucky with, others, not so lucky.

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Old 08-15-2019, 12:07 PM
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Originally Posted by bronko22000 View Post
So I think what you're looking for in this test, the way you did it, is to look for groups which had the smallest spread in velocity within that group and a pair of groups that exhibited the smallest difference in velocity?

Sorry for picking your brain. But this is very interesting and I'm sure a lot of other members are checking it out too. In all my years of reloading I was content with my method of load development. Its just been in the past month or so that I've been doing a ton of research on different techniques. What I was doing in the past was good for 100-200 yards because that's all I ever shot. Now that I want to get into long range shooting my method, to put it mildly, 'sucked"! Some rifles I got lucky with, others, not so lucky.
I have done the Newberry OCW test, and the Audette Ladder test, extensively in the past. The last two years, I've almost exclusively used the Satterlee Velocity method. I shoot at that "OCW style" target, just to give me an idea of how the groups are looking - really just to tell if I need to clean my rifle or not.

So... What SHOULD be done for an OCW test:

Line up horizontally as many target/POA's as you have incremental loads, planted at 300yrds. Shoot round robin, 1 round at each target. When finished with 3-5 rounds through each string, mark the center of each group. Then the method starts - you observe the shape of the "wave" between the centers of each group. You want to pick a load from a "flat spot" in the wave. The idea - the flat spots represent a node, meaning the slight variabilities inherent to your loading process and components won't result in as much vertical dispersion at range. Slight variability in neck tension, bullet weight, case volume, charge weights, etc... It all gets muted by falling within the node. Alternatively, loading at a wavy part of the wave would mean your load is vulnerable to increased vertical dispersion due to any of these variabilities.

Alternatively, I have been using the Satterlee method the last two years for my competition rifle, which has served me very well for long range, precision rifle competition.

For the satterlee method, you don't even need a target, just a chronograph. Shoot your incremental loads, plot the velocity curve, look for flat spots, and load in the node. The logic is a little simplistic - it effectively assumes a rifle will shoot small, simply by choosing a good bullet and putting it at the appropriate jump, so velocity consistency is the important output variable.

Since any shooting should be done at a target, I hang up a target and shoot my Satterlee method on it. Since each load is independent, I shoot independent POA's, which gives me an idea how well my rifle is grouping at that point in time (barrel life, throat erosion, copper & powder fouling). I don't put too much stock into the group sizes or shapes, but focus on the velocity curve.

Both methods work, but I can complete the Satterlee method at 100yrds effectively and efficiently, and have little dependence upon shooter influence. And do it with less rounds than an OCW or ladder.
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