How To Read OCW Test Results

[Rommel Garcia]

I went to the range today and shot my load using OCW. This is my very first time using this method. I'm having a hard time interpreting the results. Based on what I read online, you pick the load that has single-digit ES (FPS) velocity but others are looking for clusters that are adjacent to each other in terms of velocity. Then tune from there. Here's my load and test results. If I have to pick the best group, it would be Group # 5 since its got the lowest ES of velocity. It also has the smallest group size of 0.55". Group # 2 & 7 seems to have a low ES as well. But the problem is I cannot find a flat velocity between 3 charge weights which defeats the whole purpose of OCW. Shhould I pick Group # 5 and tune from there? Meaning, play with the seating depth and perhaps run a 3 charge weight, each having 3-shot group - 43.0, 43.2, 43.4. Is 43.2 a good node to tune from? Would love to hear from folks who have done OCW load testing.

 

[Whytry85]

I wouldn’t be looking for flat spots in velocity but rather POI consistencies between the charge weights for an OCW. If it were me, I’d look around the 43.2 like you said but shoot 5-15 rounds if possible to eliminate shooter error. And maybe even .1 of a grain increments to find the tuned window. Then seating depth to get the dwell time tuned to your barrels harmonics.

 

[straightshooter1]

I went to the range today and shot my load using OCW. This is my very first time using this method. I'm having a hard time interpreting the results. Based on what I read online, you pick the load that has single-digit ES (FPS) velocity but others are looking for clusters that are adjacent to each other in terms of velocity. Then tune from there. Here's my load and test results. If I have to pick the best group, it would be Group # 5 since its got the lowest ES of velocity. It also has the smallest group size of 0.55". Group # 2 & 7 seems to have a low ES as well. But the problem is I cannot find a flat velocity between 3 charge weights which defeats the whole purpose of OCW. Shhould I pick Group # 5 and tune from there? Meaning, play with the seating depth and perhaps run a 3 charge weight, each having 3-shot group - 43.0, 43.2, 43.4. Is 43.2 a good node to tune from? Would love to hear from folks who have done OCW load testing.

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Velocity flat spots simply don't tell anything about what is a good load or not. You gotta go by what you see on your targets in the progression of your loads; best seen with several POA's along a horizontal line.

 

[ShtrRdy]

As mentioned, an OCW test is all about center of group, (point of impact), compared to POI of the adjacent charge weight groups. I like to capture velocity when I do an OCW but it's more for informational use.

I'm having trouble looking at your groups placement and size.

I like how you used four shots at each powder charge. I like to do that too and then take the three closest shots.

If you haven't already, please watch this video on OCW:

 

[waveslayer]

I'd fine tune loads 4-8 looks to be a node there with the POI being very similar

 

[Rommel Garcia]

As mentioned, an OCW test is all about center of group, (point of impact), compared to POI of the adjacent charge weight groups. I like to capture velocity when I do an OCW but it's more for informational use.

I'm having trouble looking at your groups placement and size.

I like how you used four shots at each powder charge. I like to do that too and then take the three closest shots.

If you haven't already, please watch this video on OCW:

That’s a great video! It dumb it down for me enough to understand what I should do next.

As mentioned, an OCW test is all about center of group, (point of impact), compared to POI of the adjacent charge weight groups. I like to capture velocity when I do an OCW but it's more for informational use.

I'm having trouble looking at your groups placement and size.

I like how you used four shots at each powder charge. I like to do that too and then take the three closest shots.

If you haven't already, please watch this video on OCW:

Thats a great video! It sumb it down for me to understand what nodes I need to pick from my shots. In this case looks like my stable load is Groups 3,4 & 5. With these groups, I’ll load more with .1gr increments and find out the most stable, most accurate load. I’m so tempted to just stick with Group 5 and play with seating dept there

 

[Changed]

I went to the range today and shot my load using OCW. This is my very first time using this method. I'm having a hard time interpreting the results. Based on what I read online, you pick the load that has single-digit ES (FPS) velocity but others are looking for clusters that are adjacent to each other in terms of velocity. Then tune from there. Here's my load and test results. If I have to pick the best group, it would be Group # 5 since its got the lowest ES of velocity. It also has the smallest group size of 0.55". Group # 2 & 7 seems to have a low ES as well. But the problem is I cannot find a flat velocity between 3 charge weights which defeats the whole purpose of OCW. Shhould I pick Group # 5 and tune from there? Meaning, play with the seating depth and perhaps run a 3 charge weight, each having 3-shot group - 43.0, 43.2, 43.4. Is 43.2 a good node to tune from? Would love to hear from folks who have done OCW load testing.

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Despite your data, we do not have enough information to make a qualified suggestion.

What distance are you shooting these targets?
How many rounds are on the barrel?
What components are you using?
How are you loading the ammunition?
How long have you been shooting?

 

[Rommel Garcia]

What distance are you shooting these targets? 100 yards
How many rounds are on the barrel? About 150
What components are you using? Barnes 168gr TTSX, Hornady Case, Rem 9 1/2 Primer LR, H4831SC
How are you loading the ammunition? Sing stage oresss Corstwr coax, bulleted seated .050” off the lands
How long have you been shooting? 10 years