Is OCW real?

[squirtgun]

Is OCW real, or a waste of time at 100 yards for this gun and needs testing further out? Would testing further out be valid because of conditions/environment?
I'm new to reloading and by no means a pro shooter. This is the first groups trying Berger109 Hybrids seated .015" off the lands with 10 shots in .2gr increments from 33.0gr to 35.0 using Varget. Shot over a chrono to find a starting range to test for ES/SD at and pressure signs. The first two shots are low and I adjusted the scope up a 1/4 MOA for the next eight. The ballistic-X says 9 shots but that is wrong.

 

[AlNyhus]

The entire premise of 'OCW' is flawed before the first shot is fired. -Al

 

[ShtrRdy]

It looks to me like you are not doing an OCW test.

 

[shoot4fun]

Is OCW real, or a waste of time at 100 yards for this gun and needs testing further out? Would testing further out be valid because of conditions/environment?
I'm new to reloading and by no means a pro shooter. This is the first groups trying Berger109 Hybrids seated .015" off the lands with 10 shots in .2gr increments from 33.0gr to 35.0 using Varget. Shot over a chrono to find a starting range to test for ES/SD at and pressure signs. The first two shots are low and I adjusted the scope up a 1/4 MOA for the next eight. The ballistic-X says 9 shots but that is wrong.


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You make the same mistake a lot of other shooters do about OCW. You do "YOUR" version of the test instead of reading and understanding the entire process of performing a valid OCW test.
Am I saying OCW is the best way? No but it can only provide "useful" data when performed as Mr. Newberry details.
I have performed OCW in the past that gave me good answers but it is (done correctly) a time consuming process. I do not use it any longer.

 

[shoot4fun]

Here's a link to a detailed explanation of the OCW process:

Home

www.ocwreloading.com

 

[squirtgun]

I think most of you are missing the point. This was NOT an OCW test, I was just looking at velocities and pressure signs. But after 10 shots at a 6% difference in charge weight I should have been in and out of two nodes according to Mr. Newberry.
So my questions are this. Would you do a OCW test and be confident moving from target to target that your a good enough shooter to trust the results? I don't think any of the groups would be over .3" at 100 yards, is that a big enough difference to tell anything? Would you shoot a OCW test at 200 yards or is that putting in to many variables? Or do you think an OCW test would be a waste of time and components?

 

[Beiruty]

Post of photo of your shooting rifle/setup

 

[shoot4fun]

I think most of you are missing the point. This was NOT an OCW test, I was just looking at velocities and pressure signs. But after 10 shots at a 6% difference in charge weight I should have been in and out of two nodes according to Mr. Newberry.
So my questions are this. Would you do a OCW test and be confident moving from target to target that your a good enough shooter to trust the results? I don't think any of the groups would be over .3" at 100 yards, is that a big enough difference to tell anything? Would you shoot a OCW test at 200 yards or is that putting in to many variables? Or do you think an OCW test would be a waste of time and components?

The way your thread is written would easily lead most of us to "miss the point".
As a new reloader/not pro shooter maybe Like I did in the beginning) don't know what you don't know.
Not a condemnation, as nearly 50 years later I am still learning things, but a suggestion that you research the full value of things before questioning them. You may take the same loads back to the same range Monday and shoot them in the same manner but produce totally different results.
Learn the things that make your ammo more consistent.
The point of OCW was not to produce pretty groups. Initial test is to find powder nodes. There are times when choosing the best node from OCW is very difficult to read. Once a solid powder node is settled on then doing seating depth testing and, finally, testing at a longer yardage.
There are some component combinations that you could easily miss the ideal node with a .2 powder increase but others that I found nodes that were almost 2 grains wide (rare I think).

 

[dcali]

OCW isn't *not* real, exactly. But it's neither sufficient nor the best way to reliably find a good load. You're better off running a proper ladder test (velocity vs vertical impact) to select a powder charge, and then seating depth tests starting 10 thous into the lands and working back. You may have to adjust seating depth a little if you find you need to drop down a node. This has always worked for me developing loads for F class. For less demanding applications, you can cut some corners.

Basically, load development methods with names tend to be wrong and/or sub optimal (OCW, OBT, Saterlee, etc). Just stick to the fundamentals.

 

[ShtrRdy]

I think most of you are missing the point. This was NOT an OCW test, I was just looking at velocities and pressure signs. But after 10 shots at a 6% difference in charge weight I should have been in and out of two nodes according to Mr. Newberry.
So my questions are this. Would you do a OCW test and be confident moving from target to target that your a good enough shooter to trust the results? I don't think any of the groups would be over .3" at 100 yards, is that a big enough difference to tell anything? Would you shoot a OCW test at 200 yards or is that putting in to many variables? Or do you think an OCW test would be a waste of time and components?

I was just amazed that you had a load that shot better than 1/4 moa over a 1.8 grain powder weight range.

 

[squirtgun]

I was just amazed that you had a load that shot better than 1/4 moa over a 1.8 grain powder weight range.

I'm stunned myself. I would have thought if there's an optimal charge weight ( for this gun ) there would be some sign of it in that group and I don't see it or so small to be useful.

 

[squirtgun]

This is the gun. 6x47 lapua, Brux barrel 29" MTU profile 7.7 or 8 twist I think, I'd have to go look, Stiller Tac30 AW action, Shilen trigger, XLR Element chassis, Trijicon Tenmile 5-50x56 and a big arse JP brake that I would just assume remove but it's shooting to good with it and recoil is like a 223.

 

[Ned Ludd]

OCW does work. And it has nothing to do with group size. OCW is all about movement of the centerpoint of the group around the point of aim as charge (POA) weight varies. It is based on barrel harmonics. Your 10-shot group in no way proves or (even suggests) that an OCW test wouldn't have worked or that you wouldn't have observed movement of the group centerpoints about the POA. In fact, OCW works by the exact same method as does a ladder test, perhaps better known as an Audette Ladder Test. Ladder testing also works, but is generally conducted at longer distances than those used for an OCW test, at least 300 yd or so. In either type of test, if someone has a rifle that displays so little movement around the POA that interpretation of the results becomes difficult, they would only need to carry out the test at a longer distance; i.e. stretch the y-axis out a bit.

 

[CharlieNC]

I was just amazed that you had a load that shot better than 1/4 moa over a 1.8 grain powder weight range.

Yea, you got your answer! Just go with 34gr in the middle and shoot it.

 

[squirtgun]

Yea, you got your answer! Just go with 34gr in the middle and shoot it.

There is a flat spot in velocity between 34 and 34.4 and I shot some groups at 300 yards with 34.2.

 

[mikecr]

When OCW 1st came out, my impression of it's function was to find a forgiving powder charge.
With this, doing an OCW, I personally cared more about my chrono printout than any target.
Then I would move to a ladder at 300, hoping to confirm an OCW charge was best.
It never was. I always ended up tweaking it off OCW, for tightest grouping.

I believe the reason that process didn't really work is because a powder node is independent of a barrel node.
And also, coarse optimum seating needed to be found before barrel node/ladder testing.

I did find that with a BOSS tuner, I could put the barrel node right on top of an OCW load.
But without a tuner, there has been a gap to bridge(a compromise) between lowest ES and tightest grouping.

Maybe OCW has evolved to something else now, if so I'm behind on that.

 

[squirtgun]

OCW does work. And it has nothing to do with group size. OCW is all about movement of the centerpoint of the group around the point of aim as charge (POA) weight varies. It is based on barrel harmonics. Your 10-shot group in no way proves or (even suggests) that an OCW test wouldn't have worked or that you wouldn't have observed movement of the group centerpoints about the POA. In fact, OCW works by the exact same method as does a ladder test, perhaps better known as an Audette Ladder Test. Ladder testing also works, but is generally conducted at longer distances than those used for an OCW test, at least 300 yd or so. In either type of test, if someone has a rifle that displays so little movement around the POA that interpretation of the results becomes difficult, they would only need to carry out the test at a longer distance; i.e. stretch the y-axis out a bit.

Thanks Ned, that sounds like great info and longer distances is where I think I need to go to get any more out of it. I have tested charge weights with other bullets with minimal POI shift, but thought this bullet would be even harder and a waste to do that at 100 given the group and I was looking for input and alternatives. Good components are expensive and hard to come by where I live, even with the internet.

 

[ShtrRdy]

I wonder if I can get the same jumbo powder charge sweet spot in my 6mm Creedmoor if I use a 109 hybrid and Varget.

@squirtgun - what sort of velocity are you getting?

 

[squirtgun]

I wonder if I can get the same jumbo powder charge sweet spot in my 6mm Creedmoor if I use a 109 hybrid and Varget.

@squirtgun - what sort of velocity are you getting?

With the 109s and 34.2gr of Varget 2890fps, at 35gr It started showing slight pressure but another flat spot in velocity and was at 2949fps. CCI 450 primers
Wouldn't creed be a couple grains more case capacity?

 

[ShtrRdy]

With the 109s and 34.2gr of Varget 2890fps, at 35gr It started showing slight pressure but another flat spot in velocity and was at 2949fps.
Wouldn't creed be a couple grains more case capacity?

Yes, I think so. Thanks for the info.

Now I gotta find some 109's.