Optimal Charge Weight "OCW" Load Work Up. By Ryan Furman

rfurman24

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Let me know what you think. If I get enough questions I can do a follow up. I appreciate CONSTRUCTIVE criticism.
 

firearrow

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You may have mentioned it, but on the second part of your OCW Test when you are evaluating your group size and POI, will ES even play a part in your final decision? Only reason I ask is, when I’ve done this test for a few bullets for my .260 and my son’s 6.5 CM I have sometimes seen the second tightest group having the best ES. For example, my son’s CA 6.5 Mesa shooting a 120gr GMX the tightest group was .53 with an ES of 8 FPS instead of .49 MOA with a ES of 18 FPS.

I know this isn’t that big of a difference, but to make this more interesting, which way would you go if you had a group that was consistently .25 MOA with an ES of 17 FPS, and a group that was .52 MOA with a ES of 9 FPS?
 

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O ya, your video was a lot easier to understand and follow than the original OCW Test, and the 6.5 Guys version was. Good job.
 

rfurman24

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O ya, your video was a lot easier to understand and follow than the original OCW Test, and the 6.5 Guys version was. Good job.
Thank you.
 

rfurman24

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You may have mentioned it, but on the second part of your OCW Test when you are evaluating your group size and POI, will ES even play a part in your final decision? Only reason I ask is, when I’ve done this test for a few bullets for my .260 and my son’s 6.5 CM I have sometimes seen the second tightest group having the best ES. For example, my son’s CA 6.5 Mesa shooting a 120gr GMX the tightest group was .53 with an ES of 8 FPS instead of .49 MOA with a ES of 18 FPS.

I know this isn’t that big of a difference, but to make this more interesting, which way would you go if you had a group that was consistently .25 MOA with an ES of 17 FPS, and a group that was .52 MOA with a ES of 9 FPS?

No. I pay very little attention to ES during load development. I do keep the data from my labradar for later. If the load shoots it shoots. I cant count how many loads I have that consistently(this is key) shoot small at 700,800,900,1000 yards with es of 20-30fps. Often the most accurate load will not have the smallest ES. I will pay attention to it after load development by trying to keep my reloading procedure tighter. In a recent example the N565 load for the WSM in the video 210M primers give single digit ES but shoot larger groups than 250s which are running around 20FPS ES. Now if my ES is 40,50,60fps I might pay more attention. Big picture I have found the OCW and Ladder(true ladder not internet shoot in the dirt "ladder") tests to yield very forgiving loads out to at least 1100 yards.
 

firearrow

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No. I pay very little attention to ES during load development. I do keep the data from my labradar for later. If the load shoots it shoots. I cant count how many loads I have that consistently(this is key) shoot small at 700,800,900,1000 yards with es of 20-30fps. Often the most accurate load will not have the smallest ES. I will pay attention to it after load development by trying to keep my reloading procedure tighter. In a recent example the N565 load for the WSM in the video 210M primers give single digit ES but shoot larger groups than 250s which are running around 20FPS ES. Now if my ES is 40,50,60fps I might pay more attention. Big picture I have found the OCW and Ladder(true ladder not internet shoot in the dirt "ladder") tests to yield very forgiving loads out to at least 1100 yards.
Sounds good. I wanted to make sure that a load with repeatable accuracy would trump a lesser accurate load with a better ES.
 

rfurman24

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Sounds good. I wanted to make sure that a load with repeatable accuracy would trump a lesser accurate load with a better ES.
I shoot a lot of paper at long range. The target does not lie. I do strongly suggest verifying loads developed at short range at max hunting distance if not farther.
 

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Ryan I'm glad to hear I'm not the only one who doesn't obsess over small ES. One question, how far off the lands do you do your pressure/ladder test at? Great video! Cheers
 

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Why not shoot in 0.5 gr increments and select the load that has minimum velocity standard deviation?

I like Erik Cortiina's (champion benchrest shooter) approach that seating depth after acceptable charge has
been developed:
 

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Why not shoot in 0.5 gr increments and select the load that has minimum velocity standard deviation?

I like Erik Cortiina's (champion benchrest shooter) approach that seating depth after acceptable charge has
been developed.
Ryan answers this in his instructional video and in post #8.
This thread is for just that by the way, to instruct on how to perform OCW. Not to debate its efficacy.
 

jmden

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Wow. Thanks, Ryan. That took a lot of work and explains things well. Thank you!
 

J300UM

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Pretty cut and dry. Good work! I have one question pertaining to the pressure testing. Could a guy run a magnetospeed while shooting for pressure without skewing the results you’re looking for on target?
 

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Wow, thanks for doing this Ryan!! Lots of good info. I've also thought the 0.040" step size in seating depth are too large. And I agree with the smaller powder charge weight step size when doing the OCW series to aid in identifying the best load.

I have one question, but it's not related to OCW. When you're measuring velocity on increasing powder charge weight loads, and the velocity steps down for a load with more powder, do you have any idea what causes this?
 

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Excellent presentation. Thank you for putting all your time and effort into it. I would echo Edgefan's question in post 8.

PS: i wasn't able to open the target link.
 

rfurman24

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Ryan I'm glad to hear I'm not the only one who doesn't obsess over small ES. One question, how far off the lands do you do your pressure/ladder test at? Great video! Cheers
I usually start at .010 off. I used to do at the lands because pressure will be the highest but I started seeing very ugly targets with some rifles so I backed off. If I am testing different powders in a rifle that I have already completed seating depth testing with I will just use that powder. Such was the case with the two rifles/targets in the video.
 

rfurman24

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Why not shoot in 0.5 gr increments and select the load that has minimum velocity standard deviation?

I like Erik Cortiina's (champion benchrest shooter) approach that seating depth after acceptable charge has
been developed.

Eric, no doubt knows his stuff, and I agree with most of what you typed but the fact is no matter how much you want it to the lowest es does not always shoot the smallest. I have lost count of how many times this proves itself on target. I could not care less what the chrono says when the target is the final answer. As I have said countless times before, I can show you many loads with tiny es that are not as accurate as loads with larger es and they are consistent.
 

rfurman24

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Wow, thanks for doing this Ryan!! Lots of good info. I've also thought the 0.040" step size in seating depth are too large. And I agree with the smaller powder charge weight step size when doing the OCW series to aid in identifying the best load.

I have one question, but it's not related to OCW. When you're measuring velocity on increasing powder charge weight loads, and the velocity steps down for a load with more powder, do you have any idea what causes this?

Usually it is statistics. What I mean by that is I have not run into a case where that actually holds true over an average of,say, ten shots of the charges in question. This is the exact reason the Satterlee method is worthless without the rounds being put on target to visualize. I will talk about this in a future video because it leads people to chase loads that just are not going to work.
 

rfurman24

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One thing everyone reading this thread and watching my videos needs to understand is I am approaching this from a hunting stand point. I do place a high importance on accuracy(probably too much) but stability and consistent POI are more important. The internet would lead you to believe there are hunting rifles out there that can shoot .25 moa all day every day and that just is not the case. Bench rest shooters get the luxury of sighters. They also get to experiment on target. Once hunters are in the field we don't get either of those. We get one shot and it has to count. The ladder test and the OCW test are both capable of finding extremely accurate loads but as hunters we don't get to tune our loads on a day to day bases and both of these tests will show you a stable load capable of acceptable accuracy in many different conditions provided you use a stable powder.
 

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Ryan
Here is a pretty good example of exactly what you explained in your video. I have been testing 175gn ABLR's with RL-26 for my 7mag. First I did pressure test then I loaded 4 loads for groups, all done at 100yds. As you can see I got exactly what you explained in your video. I just shot the groups yesterday then saw your video today. Your right on time, now I know what I need to do next. Thanks for all your hard work and effort putting together these videos, they are so much appreciated....Ron

1-2-3 pics are the pressure test
Second group of pics will be load testing for groups, only 3 groups as I failed to charge a round with powder---oops but they were 3/4 group. IMG_20200604_154516300~2.jpg IMG_20200604_154500234~2.jpg IMG_20200604_154508925~2.jpg IMG_20201005_145428986~2.jpg IMG_20201005_145401884~2.jpg IMG_20201005_145418600~2.jpg

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First off, thank you for taking the time for doing this. Been looking forward to it since your ladder test video. Many times when reading about the OCW method, it's mentioned that three consecutive charge weights hitting close to same POA is the goal. Have you ever had test results where you have 4 or maybe even 5 charge weights do that?
 

rfurman24

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Ryan
Here is a pretty good example of exactly what you explained in your video. I have been testing 175gn ABLR's with RL-26 for my 7mag. First I did pressure test then I loaded 4 loads for groups, all done at 100yds. As you can see I got exactly what you explained in your video. I just shot the groups yesterday then saw your video today. Your right on time, now I know what I need to do next. Thanks for all your hard work and effort putting together these videos, they are so much appreciated....Ron

1-2-3 pics are the pressure test
Second group of pics will be load testing for groups, only 3 groups as I failed to charge a round with powder---oops but they were 3/4 group. View attachment 5760 View attachment 5761 View attachment 5762 View attachment 5763 View attachment 5764 View attachment 5765

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I would do seating depth testing at 66.8 if you have not already. Then I would shoot 66.7 and 66.9 but it looks like 66.8 is your load. It sits nicely in between the surrounding charges.
 

rfurman24

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First off, thank you for taking the time for doing this. Been looking forward to it since your ladder test video. Many times when reading about the OCW method, it's mentioned that three consecutive charge weights hitting close to same POA is the goal. Have you ever had test results where you have 4 or maybe even 5 charge weights do that?

Yes, when this happens it makes if difficult to see the "node". This is a rare case but it is another reason I prefer the long range ladder test. In cases like this when the rifle is that forgiving at 100 yards you will need to shoot farther to see the accuracy node and a ladder is perfect for that.
 

rfurman24

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Thanks for the video Ryan I have a question can new brass be used for this method of load development or should it be fire formed
Yes it can. I explained in my ladder test video how I deal with new vs once fired brass. I also discussed in the ladder video how to deal with barrel speed up if you find a load under 100 rounds on the barrel.
 

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Yes it can. I explained in my ladder test video how I deal with new vs once fired brass. I also discussed in the ladder video how to deal with barrel speed up if you find a load under 100 rounds on the barrel.
Thanks so much
 

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Eric, no doubt knows his stuff, and I agree with most of what you typed but the fact is no matter how much you want it to the lowest es does not always shoot the smallest. I have lost count of how many times this proves itself on target. I could not care less what the chrono says when the target is the final answer. As I have said countless times before, I can show you many loads with tiny es that are not as accurate as loads with larger es and they are consistent.
So would you expect this would be due to the hi probability of being able to achieve low ES outside of a barrel harmonics or barrel time node?

Or another way to put it is the load could have very consistent velocity where the bullet is unfortunately leaving the barrel when the shock wave is at or near the muzzle where distortion is high?
 

rfurman24

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So would you expect this would be due to the hi probability of being able to achieve low ES outside of a barrel harmonics or barrel time node?

Or another way to put it is the load could have very consistent velocity where the bullet is unfortunately leaving the barrel when the shock wave is at or near the muzzle where distortion is high?
It is a hard subject to place in type. I do believe you are describing my theory. I do not know if it will ever be proven as to why but I can assure you positive compensation does happen. I have seen loads consistently shoot under .25 moa at 1k with an ES that does not otherwise physically support the possibility.
 

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I just watched the video for the second time. Lot of information packed into it. Well done and thanks again for the effort.

I'll try to get some targets posted up as I plan on starting over with my 270 using this method.
 

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Once again great video and Very thorough. I learned a lot. I’m pretty new to reloading and this was very helpful. I’m reloading for a Christensen arms MPR 300 PRC using Berger 215, H1000, and fed215m primers. I think I’m at one of the poi nodes between 79-80. I haven’t tried seating depth test yet or smaller changes in charge. I started at 0.010. I was starting to see Slight pressure at 81 and had sticky bolt at 82. I’m glad you mention not to chase es numbers. I was about to give up since I wasn’t seeing very good es numbers. These loads gave es Values around 30-40 using a labradar. Velocity is right around 3000 FPS at 79.5 grains. Where would you go from here?
627AF0F9-5FB9-4D1C-96EE-8ACE21782777.jpeg
 
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rfurman24

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Once again great video and Very thorough. I learned a lot. I’m pretty new to reloading and this was very helpful. I’m reloading for a Christensen arms MPR 300 PRC using Berger 215, H1000, and fed215m primers. I think I’m at one of the poi nodes between 79-80. I haven’t tried seating depth test yet or smaller changes in charge. I started at 0.010. I was starting to see Slight pressure at 81 and had sticky bolt at 82. I’m glad you mention not to chase es numbers. I was about to give up since I wasn’t seeing very good es numbers. These loads gave es Values around 30-40 using a labradar. Velocity is right around 3000 FPS at 79.5 grains. Where would you go from here? View attachment 5773
What was your point of aim on the 79.5?
 

rfurman24

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79.5 is your powder charge or very close for sure. If you have not already I would do a seating depth test. If you have already or you have already told me I apologize. Sometimes it is hard for me to keep up with all the questions. After seating depth testing I would shoot 79.3 and 79.7.
 

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79.5 is your powder charge or very close for sure. If you have not already I would do a seating depth test. If you have already or you have already told me I apologize. Sometimes it is hard for me to keep up with all the questions. After seating depth testing I would shoot 79.3 and 79.7.
I haven't done the seating depth test yet. I will do that next and then try the loads you suggest. Thanks again.
 

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Ryan. This was asked above I didn’t see an answer for it. I’m curious as well. Could a guy run a magnetospeed while shooting for pressure without skewing the results you’re looking for on target?
 

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IMO anything attached to the barrel can change harmonics and in theory can affect your results, but I worked a 338lm and 300rum load up at 740yds with a v3 on and other than a minor poi shift the loads remained the same. I would like to hear others experiences with this too.


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rfurman24

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Ryan. This was asked above I didn’t see an answer for it. I’m curious as well. Could a guy run a magnetospeed while shooting for pressure without skewing the results you’re looking for on target?
With most carbon or heavier steel barrels you can. I’ve seen it affect sporter barrels though.


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Shot a couple of pressure ladders today so I thought I'd post them up for help interpreting.

Both shot at 100 yards. Winds very light and variable. About 65°
270
129 LRX .080 jump (fits magazine safely)
Virgin peterson brass
Fed 210 M
H4831SC 55.5 up to 59 in .5 increments.
I was right at 100% case fill in the 59
But didn't run into any pressure. Easy bolt lift. This would have been too hot in the old federal brass I've been running.
IMG_20201016_183323627~2.jpg
 
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And 280 rem
Dad's Old rem 700, barrel isn't floated so I spent a good amount of time trying to keep this one cool while shooting
H4831SC 54 up to 57.5 in half grain increments.
Very slight ejector mark at 57.5 with a little sticky lift.
140 SGK
.015 jump
Win LR primer
RP brass, unknown firings.
IMG_20201016_183310289~2.jpg
 
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rfurman24

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Shot a couple of pressure ladders today so I thought I'd post them up for help interpreting.

Both shot at 100 yards. Winds very light and variable. About 65°
270
129 LRX .080 jump (fits magazine safely)
Virgin peterson brass
Fed 210 M
H4831SC 55.5 up to 59 in .5 increments.
I was right at 100% case fill in the 59
But didn't run into any pressure. Easy bolt lift. This would have been too hot in the old federal brass I've been running.
View attachment 5836
I would back off the seating depth(deeper into case) in .010 increments until you are .130 off each at 58 grains. I would take the best seating depth and do the OCW from 56-58.5 in .3 increments.
 

rfurman24

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And 280 rem
Dad's Old rem 700, barrel isn't floated so I spent a good amount of time trying to keep this one cool while shooting
H4831SC 54 up to 57.5 in half grain increments.
Very slight ejector mark at 57.5 with a little sticky lift.
140 SGK
.015 jump
Win LR primer
RP brass, unknown firings.
View attachment 5837
This one I would do .010-.040 off at 54.5. Then I would take the best and load 54.0-55.5 in .3 grain increments.
 

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79.5 is your powder charge or very close for sure. If you have not already I would do a seating depth test. If you have already or you have already told me I apologize. Sometimes it is hard for me to keep up with all the questions. After seating depth testing I would shoot 79.3 and 79.7.
I shot a seating depth test today. Should I settle on 20 thousands off or continue my seating depth test past 50 thou? Sorry, can’t figure out how to rotate my picture. 409B3835-330C-47D7-B140-9F4E2E82FAB7.jpeg
 

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This is a really great video and discussion to go along with it. Before I watched I didn’t understand how much this concept revolves around barrel harmonics but it has opened up my eyes. Perfectly timed too since I was just starting to work up the 156s with N565.
 

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