When doing an OCW test recently poi at the start was near center of the dot. After the second group poi shifted down and right about 1.5”. Two consecutive groups were small but down and right. The next group was larger but poi was shifting back up to the center. The next two groups were small and back at the center. Is the lower or higher node consistently more accurate in anyone’s opinion? I’ve had rifles where poi never shifts during the entire OCW test and I’ve had some that act like this one.
OCW Testing higher poi nodes vs lower ones
- Thread starter jsthntn247
- Start date
With OCW you don't care about small groups.
You pick the center charge weight of charges that all shoot in a similar location.
You play with seating depth to tune.
300m is generally a good place to OCW. 100m generally won't show much.
You pick the center charge weight of charges that all shoot in a similar location.
You play with seating depth to tune.
300m is generally a good place to OCW. 100m generally won't show much.
RegionRat
Gold $$ Contributor
I agree with @WildBill3/75
With this OCW method, keep an eye on the goal, which is to find the widest point on the charge scale that is stable in terms of wandering POI. I know it is hard to do, but try to ignore the group size at first and concentrate on the aim point and your technique, then let the groups speak for themselves.
While it is always nice to have that also be the point with a smaller group, you take this data and go back and work on seating depth and tuning around the speed to try and close the group later.
If you find more than one node, you can always try your first pick and decide later if you also want to investigate a different one before you commit.
I find OCW and Ladder methods are more important with lighter carry guns since their barrels and stocks are more flexible and give more harmonic challenges than say a match barrel with a thicker contour and stiffer stock. Good Luck. YMMV
ETA: I won't bore you with the math, but use a target analysis program to establish the X-Y centroid of each group, then just look at the shifts in those group centers. Depending on the specific model of rifle, there is no way to answer your question about the tendency for which node is better. Back from the 60's through the 10's a Rem 700 sporting gun in 30-06 was typically happier at the higher node, but no guarantee.
Better is usually the node with the widest span before a shift, that has a decent speed stat, and where the group closes down. This combination doesn't always happen for every gun and recipe combination.
With this OCW method, keep an eye on the goal, which is to find the widest point on the charge scale that is stable in terms of wandering POI. I know it is hard to do, but try to ignore the group size at first and concentrate on the aim point and your technique, then let the groups speak for themselves.
While it is always nice to have that also be the point with a smaller group, you take this data and go back and work on seating depth and tuning around the speed to try and close the group later.
If you find more than one node, you can always try your first pick and decide later if you also want to investigate a different one before you commit.
I find OCW and Ladder methods are more important with lighter carry guns since their barrels and stocks are more flexible and give more harmonic challenges than say a match barrel with a thicker contour and stiffer stock. Good Luck. YMMV
ETA: I won't bore you with the math, but use a target analysis program to establish the X-Y centroid of each group, then just look at the shifts in those group centers. Depending on the specific model of rifle, there is no way to answer your question about the tendency for which node is better. Back from the 60's through the 10's a Rem 700 sporting gun in 30-06 was typically happier at the higher node, but no guarantee.
Better is usually the node with the widest span before a shift, that has a decent speed stat, and where the group closes down. This combination doesn't always happen for every gun and recipe combination.
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