Reading OCW Plots

[psmith]

Was reading quite a bit on this site and learning a ton. I'm trying to develop a good load for my .308 700 VS. I've gotten pretty good results at 100 yds with 168 SMK's (.5 moa). But want to use the 175's for longer distance. Have a Mk4 M3 so want something to semi track with the dials (silly, I know). Load was Lapua brass, 175 smk's Varget, and Fed 215 set to 2.82 oal (longest I can go with factory bdl metal). Following what others have done, I used Ontarget to plot the x and y distances away from the point of aim and plotted the data.

So my question is how do I interpret this data. From my understanding the load at 42.9 gr seems like the optimum one. Is this correct? My best load so far with the 168's have been at 43.5 gr but with Winchester brass which is supposed to have more case capacity so it would make sense that lapua should have similar pressures at a lower grain #. Your help and comments are appreciated. Still new to this stuff.

 

[kombayotch]

Re: Reading OCW Plots

The plot thing is mine... most don't do it. There is data on the target itself that doesn't appear on the plot, that is required.

Please post pictures of your actual targets, they are your primary source of information. Also, set your horizontal and vertical scales to the same spacing, your chart is all distorted. Your grid should be square.

With this load in a 26" barrel, you should expect to see the OCW just under 43 grains (maybe even less with your magnum primers). Velocity should be just above 2600 fps.

 

[kombayotch]

Re: Reading OCW Plots

Some will recognize this as Brad Sauve's load from 6mmbr.com:
http://www.6mmbr.com/308Win.html

The data right underneath his will be more accurate in your rifle. His barrel is only 24" long and he is using Russian primers, which aren't as potent as the Federal one's you're using.

 

[psmith]

Re: Reading OCW Plots

here's the target. Range was 200 yds with 10-15 mph wind. Its pretty awful that's why I didn't post. I did have very good accuracy with 43.5 grains of varget in the win brass with the 168's. Trying to get the 175's to shoot as well. So based on this I should step up the load a bit?

 

[kombayotch]

Re: Reading OCW Plots

OCW is run at 100 yards...

No, I wouldn't go up, it looks like you're getting a scatter group at 42.3 gr. 42.9 looks to be at about the same location as the groups before it and after. The OCW should be around there, it should be at around 2610-2630 fps.

What are the velocities at each weight?