Need help interpreting OCW test results

This is my first OCW test (also first time using this powder and bullet) and I'm having difficulty extracting meaningful data from it. The figures I have for distance and degree aren't perfect but they're pretty darn close. Nothing stands out as being an OCW "node". Does anyone see something I don't? Any suggestions for the next step in load development? I'm not the greatest marksman and conditions weren't perfect so that may be a factor. Thanks for reading.

-6.5 Creedmoor
-144 grain Berger Long Range Hybrid Target
-H4350
-CCI 200
-2.202 CBTO (~2.9 OAL)
-Hornady brass
-Factory Browning X-bolt, 28" barrel
-Shooting from the bench with bipod and rear bag, moderate wind @ 6 o'clock
-target at 100 yards
-shot "round robin" style in ~1 hour total time
-no chrono data with these shots as I didn't want to affect POI with the magnetospeed, but I did get velocity with the three foulers: 38 grains at 2478, 38.8 grains at 2563, 39.6 grains at 2617.

Obviously 41.6 and 42.0 are tightly clustered. Don't understand your measurements. To me, accuracy trumps velocity every time.

Shoot again to verify grouping and move out further, if you can

GLTaylor said:

Obviously 41.6 and 42.0 are tightly clustered. Don't understand your measurements. To me, accuracy trumps velocity every time.

Click to expand...

The measurements are distance and direction from POA to POI.
I figured I'd try this method at least once.

Hi,
Unless I am not understanding what your pics indicate... it seems you are shooting 3 shots of one charge weight at each target. If that is the case, then you are missing the point of OCW. What you need to do is shoot one shot of each charge weight at all of the different targets... 6 charge weights would mean 6 holes in each target. One from each different charge weight and then determine which different powder loads cluster well together i.e. look for example if 41.6 and 42.0 hit at the same height on the target and generally in the same spot, then you may have found a node that would put the shots into the same spot on the target which is what you are looking for. This would allow you to use a load in that weight range that you could expect to consistently hit to the same spot. If you were off 0.1 or 0.2 grains in weight, it would not matter as that load should still hit to the same area on the target. That is what they mean by an accuracy node. A range of powder weight that generally hits to the same height and spread on the target.
Are ya with me on that?
Tens

Tensilon said:

Hi,
Unless I am not understanding what your pics indicate... it seems you are shooting 3 shots of one charge weight at each target. If that is the case, then you are missing the point of OCW. What you need to do is shoot one shot of each charge weight at all of the different targets... 6 charge weights would mean 6 holes in each target. One from each different charge weight and then determine which different powder loads cluster well together i.e. look for example if 41.6 and 42.0 hit at the same height on the target and generally in the same spot, then you may have found a node that would put the shots into the same spot on the target which is what you are looking for. This would allow you to use a load in that weight range that you could expect to consistently hit to the same spot. If you were off 0.1 or 0.2 grains in weight, it would not matter as that load should still hit to the same area on the target. That is what they mean by an accuracy node. A range of powder weight that generally hits to the same height and spread on the target.
Are ya with me on that?
Tens

Click to expand...

Hmm.

Tensilon said:

Hi,
Unless I am not understanding what your pics indicate... it seems you are shooting 3 shots of one charge weight at each target. If that is the case, then you are missing the point of OCW. What you need to do is shoot one shot of each charge weight at all of the different targets... 6 charge weights would mean 6 holes in each target. One from each different charge weight and then determine which different powder loads cluster well together i.e. look for example if 41.6 and 42.0 hit at the same height on the target and generally in the same spot, then you may have found a node that would put the shots into the same spot on the target which is what you are looking for. This would allow you to use a load in that weight range that you could expect to consistently hit to the same spot. If you were off 0.1 or 0.2 grains in weight, it would not matter as that load should still hit to the same area on the target. That is what they mean by an accuracy node. A range of powder weight that generally hits to the same height and spread on the target.
Are ya with me on that?
Tens

Click to expand...

I don't think I'm with you on that hehe. My thick skull might be interfering though. Let me try to understand what you're saying. Let's say I have six different charge weights and six different targets. In that scenario, you're saying I need to fire one shot of each charge weight at each target? So each target would have six shots, each of a different charge weight? I'd have a total of 36 rounds for this theoretical test?

My understanding of the purpose of the OCW method is in alignment with yours but our means of getting there differs. Dan Newberry's site says this:
"…you will then fire your first shot from the first group of the graduated charges. You fire this shot at target number 1. Allow the barrel to cool, then fire a shot from the second graduation at target number 2. Wait for cooling of the barrel, then fire a shot from the third graduation at target number 3. Continue this "round robin" sequence until you have been through all of the targets three times. At this point you will have a three shot group on each of the targets."
His method, which I followed to my understanding, isn't the same as my understanding of yours. Are our methods different or are we lost in translation?

Loosefur,

I think you have the OCW process down pretty close. It looks like you have a node around 41 and probably around 42.2. I would load 3 each at 40.8, 41, and 41.2 and repeat. Also 42, 42.2, and 42.4 and repeat. As for barrel cooling, you don't need to let the barrel cool completely, just wait long enough fo it to cool enough for you to be able to hold the barrel. Should keep it <120 degrees F.

Good luck.

41.6 looks like where I'd work around. I'd reshoot a new set a cartridges in increments of 0.1 grain around 41.6 grains.

I like 41.6 because as you go from 41.2 to 42 grains the group centers move from .745", up to 1.032" and back to .777" and the centers start and end at the same angle from the POA. If you work around the 41.6gr load you should narrow that group size variation down a bit but and the angle will vary less too. Once you get to the best load try changing the seating depth a little and see if you can squeeze just a little more precision out of the group size.

OCW isn't really designed to give you the tightest groups, it's used to give you the most repeatable group accuracy (where the group center impacts compared to the POA). You might have slightly worse precision (the group size) but you should impact the target more reliably under differing environmental conditions and load component variations.

Thanks for the advice Doom2. I'll do that and see where it puts me, then perhaps play with seating depth.

Great advice Rammac, I appreciate your input. I wondered about that exact thing.

Here is a link to a good target to use.

Doom2 said:

Here is a link to a good target to use.

Practical Riflery and OCW Forums-OCW OFFICIAL TEST TARGET

The file can be downloaded by clicking on the following links MOA Target in PDF format MOA Target in JPG format

www.tapatalk.com

Click to expand...

Heck yeah! That's slick! Thank you.

As pointed out above, 41.0 is your OCW node as it incurs minimal POI shift from 40.8 to 41.2.

Next step per OCW is to load 41.0 and adjust seating depth to tune group size. You should find that powder charges from 40.8-41.2 will group similarly, hence the robustness of the node—and at 41.0 should show some temp resilience as well.

^^^^This. With so much info available, the actual intent of a method is often lost and misrepresented. Your shooting very well and understand that the point of the OCW method is similar POI rather than group size. Group size will be the fine tuning of the load (seating depth and final load withing that node). Do as new2mud recommends and stretch it out.