OCW testing and confused

[Boogie]

I went to the range today trying to work up a load for my Savage M12 f/tr. This is the first time I've tried the OCW method and I'm a bit confused. Mainly because all the groups are so close. Also after shooting the test at 100yds I did it again at 300yds. Don't know if your supposed to do that but it seems the tightest groups at 100 are the loosest at 300.

Most of my shooting is done at 300 and 600 yds which is why I did the 300 yd test. I sure would appreciate some help deciphering this target.

Anyway here's the specs and the 100yd target. If anyone wants to see the 300 yd target let me know and I'll post it.

Lapua brass
Varget powder
CCI BR2 primers
Berger 175 gr LRBT Target. Loaded .020" off the lands

 

[Papagallos]

If most of your shooting takes place at distances of 300 and 600 yards, then fine tune a load for those distances. 100 yards means squat, especially for your distance needs. I've seen a rifle shoot in the .1s at 100 yards, but at distance, it plain sucks.

*****Disclaimer: I am far from an expert in this area.

 

[scudzuki]

OCW tests are typically run at 100 yards.
Running OCW tests at greater distance reveals no benefit.
You are not looking for tight groups. You are looking for a node, a sweets spot, that is a small range of charges that occupy the same part of the target; they indicate a charge range that result in the bullets exiting the muzzle when the pulse wave that runs down the barrel has bounced back to the breech.
I have run a half dozen OCW tests and never had fewer than 12 targets, with charge increments of .2 grains when charges are in the 2x. grain range and .3 grain increments in the 4x. grain range (.223 and 308, for example).
You have tested a very narrow range of charges; a node can span .6 or more grains and your entire test spanned 1.2 grains. When I run an OCW, I see a trend as the individual groups move around the POA but for at least one and sometimes 2 ranges of charges spanning .6 or .8 grains, the groups will land in the same part of the target, a "group of groups" is what I look for.

I'd like to see the results if you rerun the test, this time starting at the minimum book recommended charge and running up to and perhaps past the book max, watching for signs of pressure as you approach the max. Based on what I see, you could have a node right there at 42.3 to 42.9.

Joe

 

[diego-ted]

not enough data in your test. You need to go from 42-44+? gr in .3-5gr increments to find like POI along with scatter nodes!

here is one of my recent tests.



Diego

 

[JB02]

not enough data in your test. You need to go from 42-44+? gr in .3-5gr increments to find like POI along with scatter nodes!

here is one of my recent tests.



Diego

Ditto. My OCWs have around 8-10 different groups. You are looking for a consistent charge weight, the middle of three that group decently. Then you adjust seating depth to close the groups. You're wasting your time moving out.

If you have a couple of good charge weights that you can't decide between, then test them out at longer distances AFTER you've played with seating depth. OCW tests are done at 100 yds. Ladder tests are done at long range.