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Discussion Starter · #1 ·
I've done ladder workups for every new combination that I've tried so far... Stumbled across OCW process (linky!) after some browsing on barfcom (did I get that right, Knight?) and I'm considering trying it with the new CZ that I have.

How do you guys work up loads?
 

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I've done ladder workups for every new combination that I've tried so far... Stumbled across OCW process (linky!) after some browsing on barfcom (did I get that right, Knight?) and I'm considering trying it with the new CZ that I have.

How do you guys work up loads?
seems like a viable option...I saved the link (or is that linky? ;) ) for future analysis...as long as you aren't running above manufacturer's top-end should be an interesting process

look forward to a report
 

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Interesting method. I'm still trying to work up loads for my bbl AR but don't have a convenient method of conducting a ladder test at more than 100 yards which makes the ladder test basically pointless. This may be exactly what I've been looking for. Was planning to do some load testing Sunday morning before wind and temperature pick up so I might try this out.

Up until now I've just been loading groups of 9 cartridges at each of 5 evenly spaced charge weights from min to just under max load (waiting a while before I try loading maximum data since I just started rolling my own). Then 3 groups of 3 shots each for each charge weight (trying to eliminate shooter error by shooting multiple groups with each load), find what I believe to be my accuracy sweet spot, further testing in that smaller range of charges to narrow my load and verify my theory, before finally settling on what I believe to be my most accurate load.

It really makes sense to me to try to load at the middle of the rifle's specific accuracy node rather than try to pick the charge weight which yields the most accurate groupings, for consistency sake. Small differences such as case capacity, temperature, humidity, and small variances in powder charge will create changes in your load's performance when all thrown together. Therefore buffer room on either side of the spectrum really seems like a good idea (to me at least). Looking forward to what Fred, JustSomeGuy, and 57k have to say on this method...

***waiting....***
 

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This was interesting. I have always felt that the physical properties of the gun were not given enough consideration when doing load development and that some aspect of barrel harmonics was neglected. This OCW or optimum charge weight loading sequence seems to try to take into consideration the basic physics of the rifle and is certainly worth trying.

The same thing applies to pistols. There has to be a certain mechanical optimum moment for the bullet to exit the barrel, as I too have noticed that the best shooting load is not always that with the best numbers, so something else has to be in play. That seems to be the basic mechanics of the gun. If you can find a series of loads that best meet the mechanical needs of the pistol, then something in the center of those loadings will always produce very good results. So yeah, this is a viable experiment for both rifles and pistols.
 

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Discussion Starter · #5 ·
I will be running these loads over the chrono tomorrow.

OCW loading:

Pulled load data from my Loadbooks, USA manual, Lyman #49, and Hodgdon. Lyman really surprised me - they have 28.0gr of Varget listed as max for 223. I began working this load up, and I stopped at 27.2gr because of case volume. I'm worried about bullet rebound, that's how high the powder is in the case.

"Sighters" - 1 ea at low end of the charge range to adjust POI

24.1
24.6
25.1

Test groups - 3 ea, approximately 2% gradation

25.6
25.8
26.0
26.2
26.4
26.6
26.8
27.0 <--- max load per Hodgdon
27.2 <--- recommended to go over max load by one gradation.

Ladder loading:

5ea at 0.3gr intervals

24.0
24.3
24.6
24.9
25.2
25.5
25.8
26.1
26.4
26.7
27.0

Essentially testing the same range, but wondering if I find a sweet spot at different points in the workups. I'll post results late tomorrow.
 

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Discussion Starter · #6 ·
Well I think 2.260" (mag length) for these 52gr is too long. Although I had some good results, the bolt was very hard to close, and when I inspected a chambered round, I could see the grooves on the bullet...

Not groovy, man.

OCW results next post.
 

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Discussion Starter · #7 ·
PLEASE USE PUBLISHED MANUFACTURER'S DATA FOR YOUR LOADS. USE THIS ONLY FOR REFERENCE.

Conditions:

Date: 9/6/14
Location: Cheney Outdoor Shooting Range, Pretty Prairie, KS
Range: 100 yard
Temp: 68 deg F
Humidity: 80%
Pressure: 30.3 in
Wind: 0-10 NNE
Sky: Clear
Gun: CZ 527 Varmint 24" 1:9 twist

Components:

Powder: Varget
Primer: CCI 400
Bullet: 52gr Hornady HPBT
Brass: Lapua Match @ 1.750"
COAL: 2.260"

OCW Results:

Load: 25.6gr
Avg Vel: 3120
SD: 15.1
ES: 29
Group: 0.649"

Load: 25.8gr
Avg Vel: 3137 (all three shots, about 5 minutes apart each registered 3137fps)
SD: 0
ES: 0
Group: 1.091"

Load: 26.0gr
Avg Vel: 3185
SD: 34.1
ES: 68
Group: 0.843"

Load: 26.2gr
Avg Vel: 3197
SD: 15
ES: 30
Group: 0.637"

Load: 26.4gr
Avg Vel: 3217
SD: 31.9
ES: 63
Group: 1.079"

Load: 26.6gr
Avg Vel: 3241
SD: 12.2
ES: 24
Group: 1.044"

Load: 26.8gr
Avg Vel: 3265
SD: 9.8
ES: 20
Group: 0.617"

Load: 27.0gr
Avg Vel: 3317
SD: 14.4
ES: 25
Group: 1.294"

Load: 27.2gr
Avg Vel: 3311
SD: 4.6
ES: 7
Group: 2.173"

Comments:

First of all, this was loaded to the instructions I linked in my previous posts. Second of all, this is my first outing with VERY nice brass and a powder that everybody adores in 223. I am a definite believer - I scored some good groups and had some very nice ES and SD's, even one that registered 3137fps 3 times in a row, with 8 other rounds between each shot. I did notice the velocity drop at the very top end (a .2gr add shows a drop of 6fps) and I believe if I went any further that I would have seen more of the same. 27.2gr of Varget fills the case to about 1/16" from the case mouth, so I quit there even though Lyman #49 has pressure rated data with a max at 28gr. Honestly I don't know how they fit that much in there.

Now continuing on the OCW instructions, I used OnTarget and calculated the center of each group, and plotted it on a new target.



There are 3 ranges that I believe fall into a good optimal charge weight range.

26.0gr, 26.2gr, 26.4gr - Purple
Avg Vel: 3200
Max Vel: 3252
Min Vel: 3152
ES: 100
SD: 26.82
Avg Group: 0.853"

26.4gr, 26.6gr, 26.8gr - Green
Avg Vel: 3241
Max Vel: 3276
Min Vel: 3189
ES: 87
SD: 25.48
Avg Group: 0.913"

26.6gr, 26.8gr, 27.0gr - Red
Avg Vel: 3274
Max Vel: 3325
Min Vel: 3228
ES: 97
SD: 33.05
Avg Group: 0.985"

The green triangle is the smallest and its charge weight values have some of the smaller groupings, however the red triangle's charge weights have the three smallest ES and SD values of the test. The next step is to load one at each charge weight in the group at 1% above, right at, and 1% below the optimal charge weight, and see if there is MOA accuracy. If not, then there was an anomaly in the original test. The OCW instructions note that seating depth can affect accuracy, and I believe I seated the bullets too long today, so I expect the accuracy to improve as one, I adjust the seating depth, and two, as this Lapua brass fireforms itself to my chamber.

Let me know what you think. Ladder results next post.
 

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Discussion Starter · #8 ·
PLEASE USE PUBLISHED MANUFACTURER'S DATA FOR YOUR LOADS. USE THIS ONLY FOR REFERENCE.

Conditions:

Date: 9/6/14
Location: Cheney Outdoor Shooting Range, Pretty Prairie, KS
Range: 100 yard
Temp: 72 deg F
Humidity: 70%
Pressure: 30.3 in
Wind: 0-10 NNE
Sky: Clear
Gun: CZ 527 Varmint 24" 1:9 twist

Components:

Powder: Varget
Primer: CCI 400
Bullet: 52gr Hornady HPBT
Brass: Lapua Match @ 1.750"
COAL: 2.260"

Ladder Results:

Load: 24.3gr
Avg Vel: 2927
SD: 41.9
ES: 115
Group: 0.787"

Load: 24.6gr
Avg Vel: 2974
SD: 26.1
ES: 67
Group: 1.204"

Load: 24.9gr
Avg Vel: 2982
SD: 17.1
ES: 47
Group: 1.336"

Load: 25.2gr
Avg Vel: 3062
SD: 23
ES: 63
Group: 0.906"

Load: 25.5gr
Avg Vel: 3095
SD: 25.8
ES: 65
Group: 0.571"

Load: 25.8gr
Avg Vel: 3155
SD: 11.3
ES: 30
Group: 1.318"

Load: 26.1gr
Avg Vel: 3174
SD: 23.6
ES: 60
Group: 0.985"

Load: 26.4gr
Avg Vel: 3209
SD: 18
ES: 47
Group: 1.039"

Load: 26.7gr
Avg Vel: 3242
SD: 17.8
ES: 39
Group: 0.668"

Load: 27.0gr
Avg Vel: 3272
SD: 12.6
ES: 33
Group: 1.178"

Comments:

I think results here are pretty consistent with what I had been seeing out of the OCW test. If I were to pick a couple loads and chase accuracy in them, I would look at 26.7gr and 25.5gr. Since the OCW test eliminated a low charge weight like 25.5gr (in part, I think, due to unreliable ignition - most BR guys look for 98%+ case fill for powder), I'll be looking more towards the high end.

Since I had good accuracy and pretty decent numbers at 26.7gr in both tests, I think I'll be choosing that green triangle range from the OCW. 26.6gr will be my OCW value.
 

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Discussion Starter · #9 ·
Just a quick graph of charge vs velocity, showing a good linear progression and correlation between tests throughout the charge weights all the way to the top end.

 

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Not that I'm any kind of rifle expert, but the work you put in doing these two comparative test methods is exemplary. You seem to have zeroed in on around 26.7-26.8grns with your current OAL as your most accurate and repeatable loading. Hopefully slight variations in OAL will continue to provide excellent results too. It would be interesting to see if you could try these in another 223 rifle if you have one or could borrow one for testing, thus proving the value of the OCW (optimum charge weight) method.

Good work and let us know what else you come up with.
 

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Discussion Starter · #11 ·
Not that I'm any kind of rifle expert, but the work you put in doing these two comparative test methods is exemplary. You seem to have zeroed in on around 26.7-26.8grns with your current OAL as your most accurate and repeatable loading. Hopefully slight variations in OAL will continue to provide excellent results too. It would be interesting to see if you could try these in another 223 rifle if you have one or could borrow one for testing, thus proving the value of the OCW (optimum charge weight) method.

Good work and let us know what else you come up with.
Thanks JSG. I'm not surprised that my best loads are near the top because of the compressed charges. I think that most rifles would shoot well with this load because it is a slower powder, but I think you would find a slight variation rifle to rifle just because of the physical differences. Testing this method at 200 to 300 yards would show even more differences and could get you even closer to a true optimal charge weight. I may try this same load in my AR, just to see where it likes it.

I fear that I may have to re-do this whole workup (likely staying near the top end) because of my OAL. I did some more fiddling around with this 52gr bullet and its ogive is so short that I may have to seat it at 2.200", whereas this test was at 2.260". I'm not worried about pressure changes - fred has said that increasing the OAL in rifle gives the gas a smaller volume to expand into, and I think with the bullet in the lands is worst case scenario. I know we're only talking about 1/16" of an inch, but with the powder very near the case rim, and filling the case past 27gr, I'll have to watch for any rebound. I may load one up today and let it sit for a week to see how much it rebounds, if any.
 

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Thanks JSG. I'm not surprised that my best loads are near the top because of the compressed charges. I think that most rifles would shoot well with this load because it is a slower powder, but I think you would find a slight variation rifle to rifle just because of the physical differences. Testing this method at 200 to 300 yards would show even more differences and could get you even closer to a true optimal charge weight. I may try this same load in my AR, just to see where it likes it.

I fear that I may have to re-do this whole workup (likely staying near the top end) because of my OAL. I did some more fiddling around with this 52gr bullet and its ogive is so short that I may have to seat it at 2.200", whereas this test was at 2.260". I'm not worried about pressure changes - fred has said that increasing the OAL in rifle gives the gas a smaller volume to expand into, and I think with the bullet in the lands is worst case scenario. I know we're only talking about 1/16" of an inch, but with the powder very near the case rim, and filling the case past 27gr, I'll have to watch for any rebound. I may load one up today and let it sit for a week to see how much it rebounds, if any.
I'm not quite sure I understand your comment about what Fred said, since increasing the OAL would increase the volume of the case available to the powder. Granted you don't want to be into the lands, especially when dealing with loads intended to be universal for use in different rifles, so loading extremely long is not an option. Again, I'm not quite sure I get the gist of your reference to Fred's comment since I don't see it in this thread and increasing the OAL would give the GAS more room, but the BULLET less room. Seeing as the load seems to be at or above 100% load density with this bullet, a lighter mid range one in weight at that, and as far out as it can be in that barrel, it seems likely that exploring longer OAL's would be a non-starter. From what I gather, it would seem shortening the OAL by .001-.002 or so would seem more reasonable as a place to start for fine tuning for accuracy with the powder in the 26.X ranges. But like I said before, I am not much of a rifle shooter, though I do own a couple in this caliber.
 

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Discussion Starter · #13 ·
I'm not quite sure I understand your comment about what Fred said, since increasing the OAL would increase the volume of the case available to the powder. Granted you don't want to be into the lands, especially when dealing with loads intended to be universal for use in different rifles, so loading extremely long is not an option. Again, I'm not quite sure I get the gist of your reference to Fred's comment since I don't see it in this thread and increasing the OAL would give the GAS more room, but the BULLET less room. Seeing as the load seems to be at or above 100% load density with this bullet, a lighter mid range one in weight at that, and as far out as it can be in that barrel, it seems likely that exploring longer OAL's would be a non-starter. From what I gather, it would seem shortening the OAL by .001-.002 or so would seem more reasonable as a place to start for fine tuning for accuracy with the powder in the 26.X ranges. But like I said before, I am not much of a rifle shooter, though I do own a couple in this caliber.
Here's the post I was referencing:

Because there are NOT the same. The fastest rifle powder is still slower than the slowest pistol powder. The smallest practical rifle case volume (223) is larger than the 44mag. So combine the two, you almost can't get enough of some rifle powders into a case to detonate a gun.
You can compress most rifle powders 100% w/ no ill affects, so seating deeper, not an issue. With pistols, you are reducing the already small case cap, compared to rifles, & using uber fast powders. Throw in that you can't get into the rifling with most bullets in handguns to spike pressures. If you do, then your handgun load will spike just like a rifle load. In revolvers, you are miles away from the rifling. The deeper you seat a rifle bullet, the further from contact to the rilfing, the powder has time to expand before meeting resistance. The closer the rifling, the less time the higher the pressures. So why I say they are opp, because for the most part that is true.
 

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Ok... now I understand. Fred is saying basically what I said. Generally increasing the OAL will give more room for the GAS to expand IN THE CASE before the bullet hits the rifling. However, if you are already on the lands, then you can't go that way as pressure will spike and you are already at or near the maximum for that powder/bullet combination. So... with rifle powders, which are pretty slow burning, you can compress them somewhat to get off the lands without spiking pressure merely by compression of the powder.
 

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Discussion Starter · #15 ·
Ok... now I understand. Fred is saying basically what I said. Generally increasing the OAL will give more room for the GAS to expand IN THE CASE before the bullet hits the rifling. However, if you are already on the lands, then you can't go that way as pressure will spike and you are already at or near the maximum for that powder/bullet combination. So... with rifle powders, which are pretty slow burning, you can compress them somewhat to get off the lands without spiking pressure merely by compression of the powder.
So, you think I can adjust the COAL from 2.260" to 2.200" without really affecting accuracy or pressure?

The more and more I think about this workup, it's just a modified ladder workup, and you're looking more at what your gun is doing.

Think about it - you are still increasing in a linear fashion. Normally ladder workups for small capacity cases like 223 Remington are normally 0.2gr to 0.3gr increments. For most powders, as Newberry recommends 0.7% to 1.0%, that's really about 0.2gr to 0.3gr if you look at most powders at max load in the 23-27gr range. From my reading and very limited experience, most rifles like loads in the upper mid to near max loads. This can vary based on the cartridge and rifle, but Newberry's loading steps are basically this:

  • Choose bullet and max charge
  • Decrease by 7 to 10 percent
  • Load 1 cartridge at the starting charge
  • Add 2 percent, and load one cartridge.
  • Add another 2 percent, and load one more final "fouler / sighter" cartridge.
  • Add 0.7% to 1.0%, and load 3 to 5 at this charge weight
  • Repeat the 0.7% to 1.0% addition and loading until you reach approximately 1% above your maximum charge weight

Then you fire round robin style at separate targets, watching the POI shift across your charge range.

Like I said, really just a modified ladder workup designed to get you into the mid to max charge weights were most powders will be the most consistent.
 

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I only scratched the surface of the elaborate post...but so far EXCELLENT write-up...I am gonna read through it all this evening after work wraps up...

Very well drawn-out and executed sir...
 

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Discussion Starter · #17 ·
So, you think I can adjust the COAL from 2.260" to 2.200" without really affecting accuracy or pressure?

The more and more I think about this workup, it's just a modified ladder workup, and you're looking more at what your gun is doing.

Think about it - you are still increasing in a linear fashion. Normally ladder workups for small capacity cases like 223 Remington are normally 0.2gr to 0.3gr increments. For most powders, as Newberry recommends 0.7% to 1.0%, that's really about 0.2gr to 0.3gr if you look at most powders at max load in the 23-27gr range. From my reading and very limited experience, most rifles like loads in the upper mid to near max loads. This can vary based on the cartridge and rifle, but Newberry's loading steps are basically this:

  • Choose bullet and max charge
  • Decrease by 7 to 10 percent
  • Load 1 cartridge at the starting charge
  • Add 2 percent, and load one cartridge.
  • Add another 2 percent, and load one more final "fouler / sighter" cartridge.
  • Add 0.7% to 1.0%, and load 3 to 5 at this charge weight
  • Repeat the 0.7% to 1.0% addition and loading until you reach approximately 1% above your maximum charge weight

Then you fire round robin style at separate targets, watching the POI shift across your charge range.

Like I said, really just a modified ladder workup designed to get you into the mid to max charge weights were most powders will be the most consistent.
With this general theory in mind, I loaded up a workup of Benchmark and 52gr HPBT's, I think this will work even better than Varget and the 52's. I find Varget to be very accurate, and although it meters poorly, I think you get really good consistency with the powder itself if you weigh/trickle each charge. I know that's not good for you progressive folks, but after obsessing over everything from checking meplats to ensure nothing's crushed, to measuring each case with a comparator and each round for OAL, trickling powder is just another step. That being said, this is about the slowest powder I'd use for these lightweights. If Benchmark doesn't prove to be well suited for what I'm loading, I'll move on to AA2015 or TAC.

Nosler and Lyman's data both noted Benchmark was the most accurate powder tested in this bullet weight range. I loaded 3 foulers/POI adjustment rounds at 23.4, 23.9, and 24.4, then added 2% again and began my actual workup at 1.0% increments to the top end. I set these at 2.200", which when I measured it again with this bullet, was the maximum OAL and I think is actually on the lands. In the future to tune this round, I may back off to 2.180", but for now, I'll watch the pressure signs as I work up the load and go from there. I didn't have any case fill problems this time around, but Benchmark is significantly more dense.

I find that I'm saving about 30-40% on my workups, and with how variable powder and bullets can be in my area, this is pretty significant to me. I would like to buy in bulk eventually once I really nail down what each of my guns like, but for now, this works.
 

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With this general theory in mind, I loaded up a workup of Benchmark and 52gr HPBT's, I think this will work even better than Varget and the 52's. I find Varget to be very accurate, and although it meters poorly, I think you get really good consistency with the powder itself if you weigh/trickle each charge. I know that's not good for you progressive folks, but after obsessing over everything from checking meplats to ensure nothing's crushed, to measuring each case with a comparator and each round for OAL, trickling powder is just another step. That being said, this is about the slowest powder I'd use for these lightweights. If Benchmark doesn't prove to be well suited for what I'm loading, I'll move on to AA2015 or TAC.



Nosler and Lyman's data both noted Benchmark was the most accurate powder tested in this bullet weight range. I loaded 3 foulers/POI adjustment rounds at 23.4, 23.9, and 24.4, then added 2% again and began my actual workup at 1.0% increments to the top end. I set these at 2.200", which when I measured it again with this bullet, was the maximum OAL and I think is actually on the lands. In the future to tune this round, I may back off to 2.180", but for now, I'll watch the pressure signs as I work up the load and go from there. I didn't have any case fill problems this time around, but Benchmark is significantly more dense.



I find that I'm saving about 30-40% on my workups, and with how variable powder and bullets can be in my area, this is pretty significant to me. I would like to buy in bulk eventually once I really nail down what each of my guns like, but for now, this works.

Funny you picked that combo. I just attempted my own OCW load testing on 52gr MatchKings over Benchmark this weekend. My testing is nowhere near as detailed as yours has been, but it will be interesting to find out if our results correlate in any way...


All three of my fouling shots were the three shots at 23.9gr and I used them to get my optic on target. Then I completed my OCW testing (30-50 seconds between each shot), increasing my powder charge on each shot by 0.2gr. Each one is labeled above the target by order of shot and charge weight. Looks like 24.8gr is going to be my best bet for consistency (+\-0.1gr still gives me nice groups at the same general POI) unless the group at 24.7 is a fluke, but I've loaded 25 more rounds to confirm this. I loaded 5 rounds each of 24.7, 24.9, 25.1, 25.3, and 25.5. I'll probably test the second batch to confirm this weekend.



Sent from my iPad using Tapatalk
 

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So, you think I can adjust the COAL from 2.260" to 2.200" without really affecting accuracy or pressure?

The more and more I think about this workup, it's just a modified ladder workup, and you're looking more at what your gun is doing.

Think about it - you are still increasing in a linear fashion. Normally ladder workups for small capacity cases like 223 Remington are normally 0.2gr to 0.3gr increments. For most powders, as Newberry recommends 0.7% to 1.0%, that's really about 0.2gr to 0.3gr if you look at most powders at max load in the 23-27gr range. From my reading and very limited experience, most rifles like loads in the upper mid to near max loads. This can vary based on the cartridge and rifle, but Newberry's loading steps are basically this:

  • Choose bullet and max charge
  • Decrease by 7 to 10 percent
  • Load 1 cartridge at the starting charge
  • Add 2 percent, and load one cartridge.
  • Add another 2 percent, and load one more final "fouler / sighter" cartridge.
  • Add 0.7% to 1.0%, and load 3 to 5 at this charge weight
  • Repeat the 0.7% to 1.0% addition and loading until you reach approximately 1% above your maximum charge weight

Then you fire round robin style at separate targets, watching the POI shift across your charge range.

Like I said, really just a modified ladder workup designed to get you into the mid to max charge weights were most powders will be the most consistent.
Well... it is to a certain degree a modified ladder, but this also takes into account the drift caused by the mechanics of the rifle/barrel harmonics, or vibration rate at the chamber end rather than at the muzzle end at the time the bullet leaves the barrel. So the "round robin" targeting sort of lets you know when the barrel's muzzle is vibrating the least according to this theory. This also, according to the OCW plan, allows for the same load to be fired in multiple rifles with good accuracy which is nothing to sneeze at.

Since, like you say, most of the time, the best loads are approaching or very near maximum for a particular powder/bullet combination, it pays to start off the loading procedure a bit higher than the minimums that might be suggested for a known combination listed in the books since the minimum only describes what pressure is required to get into the bottom end of the powder's more optimum range anyway, and really has little to do with safety from an "overpressure" standpoint.

Frankly, I kind of like this approach, and since several of the members are now trying it out, I think we should all get some pretty good data about how well this works out. It seems to work in pistols, at least as far as I can tell from data with 9mm and 40cal using various guns, in that those that can accept the OAL chosen for a good load seem to all produce pretty much the same accuracy if the gun itself is up to it, but other mechanics are also involved by the moving parts. Rifles, having longer barrels and thus being more sensitive to the vibration effects supposedly accounted for using the OCW method, would benefit much more from the round robin targeting and optimum charge weight once you find it.
 

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Discussion Starter · #20 ·
Funny you picked that combo. I just attempted my own OCW load testing on 52gr MatchKings over Benchmark this weekend. My testing is nowhere near as detailed as yours has been, but it will be interesting to find out if our results correlate in any way...


All three of my fouling shots were the three shots at 23.9gr and I used them to get my optic on target. Then I completed my OCW testing (30-50 seconds between each shot), increasing my powder charge on each shot by 0.2gr. Each one is labeled above the target by order of shot and charge weight. Looks like 24.8gr is going to be my best bet for consistency (+\-0.1gr still gives me nice groups at the same general POI) unless the group at 24.7 is a fluke, but I've loaded 25 more rounds to confirm this. I loaded 5 rounds each of 24.7, 24.9, 25.1, 25.3, and 25.5. I'll probably test the second batch to confirm this weekend.
I loaded all the way to 26.3gr. Hodgdon online recommended 26.0gr as a maximum; Lyman was just under that at 25.7gr. I was surprised to see Nosler's data for their custom competition line go all the way up to 26.5gr, which would be right at 100% case fill I believe (although they say 102 or 105%)

I will let you know how these rounds turn out - I'm hoping to get out again this Saturday, we'll have to see what the weather does.

Well... it is to a certain degree a modified ladder, but this also takes into account the drift caused by the mechanics of the rifle/barrel harmonics, or vibration rate at the chamber end rather than at the muzzle end at the time the bullet leaves the barrel. So the "round robin" targeting sort of lets you know when the barrel's muzzle is vibrating the least according to this theory. This also, according to the OCW plan, allows for the same load to be fired in multiple rifles with good accuracy which is nothing to sneeze at.

Since, like you say, most of the time, the best loads are approaching or very near maximum for a particular powder/bullet combination, it pays to start off the loading procedure a bit higher than the minimums that might be suggested for a known combination listed in the books since the minimum only describes what pressure is required to get into the bottom end of the powder's more optimum range anyway, and really has little to do with safety from an "overpressure" standpoint.

Frankly, I kind of like this approach, and since several of the members are now trying it out, I think we should all get some pretty good data about how well this works out. It seems to work in pistols, at least as far as I can tell from data with 9mm and 40cal using various guns, in that those that can accept the OAL chosen for a good load seem to all produce pretty much the same accuracy if the gun itself is up to it, but other mechanics are also involved by the moving parts. Rifles, having longer barrels and thus being more sensitive to the vibration effects supposedly accounted for using the OCW method, would benefit much more from the round robin targeting and optimum charge weight once you find it.
Yeah, like I said earlier, you watch POI shift (or moreso for the lack of shift) on the way up the charge range. I'm not sure what effect the round robin targeting really has except that you know within a few rounds how high you can push the charge range until you start seeing signs of pressure. I think it's also psychological - I know I try really hard to get good groups, and one poor group could frustrate me enough to throw the following groups off. With the round robin style, it's one round at one charge at one target, then on to the next one.

I like the approach too - instead of chasing one load that happened to be accurate, you are chasing a range that proves consistent POI. So far in my testing of this method, I believe that low SD and ES values also occur in a truly optimum charge weight range. The other thing that I like is that this method, for the progressive press users out there, is that once you settle on a charge weight, you no longer need to worry about powder charges AS MUCH. I capitalize that because we always have to be careful when dealing with components, but think about it - if you've gone through the entire testing regimen, you've shown that 3 rounds at 1% below you optimum charge, right at your optimum charge, and 1% above your optimum charge can shoot MOA accuracy - now I don't know about you, but unless I'm using a powder that meters very poorly (think long grain extruded powders that can "bridge" in a powder drop like Varget), my equipment will routinely do within +/- 0.5%. That's instant peace of mind and reliability with a round that will be accurate no matter the conditions.
 
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