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OCW help...168 and 175 grain

turbohardtop

Sergeant
Full Member
Minuteman
Mar 1, 2010
217
1
50
Austin, TX
I finally had a chance to test the OCW method out to 200 yards. the components are as follow, LC LR brass, Wolf LRP, Varget, and SMK 175 (top 2 targets) and 168 (bottom 2 targets). All are 3 shot fired sequentially (round robin) from one load to another. The first target of the 175 grain, I had to adjust the scope to get the following shots on target as the first shot in the test was way low. Please comment and let me know which target of each bullet weigh you think should be used to fine tune. Thanks in advance.

IMG_0513_rotated.jpg
 
Re: OCW help...168 and 175 grain

For the 175, the 44.3 to 44.9 seems to stay pretty tight. If it were me, I’d run the upper end of the data a couple of times to see if it consistently repeats itself.

On the 168, I agree you probably end up around 45gr. Just guessing, but I bet 45.3gr would have been tight, but you pulled it a little.
 
Re: OCW help...168 and 175 grain

168 45gr
175 44.3 looks good but 44.6 does not look bad. Survey the CW range between 43.1 and 44.8 to find where it shoots best.

Remember OCW is looking NOT for the one CW that shoots well, but for the RANGE over which the loads all shoot well.
 
Re: OCW help...168 and 175 grain

By the OCW method, shouldn't you mark the center of each three shot group and compare <span style="font-style: italic">that</span> point among the targets? Otherwise I'm not sure how your method is any different from the old standby of shooting a bunch of groups and picking the one that looks the best.
 
Re: OCW help...168 and 175 grain

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jsthntn247</div><div class="ubbcode-body">175s 44.3
168s. 45.2
Play with seating depths with these charges </div></div>

For the 168 did you mean 45 grains?
Should I do another test with
44.1 44.2 44.3 44.4 44.5 for 175
44.8 44.9 45.0 45.1 45.2 for 168

Thanks everyone for you input.
 
Re: OCW help...168 and 175 grain

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: groovinpickle</div><div class="ubbcode-body">By the OCW method, shouldn't you mark the center of each three shot group and compare <span style="font-style: italic">that</span> point among the targets? Otherwise I'm not sure how your method is any different from the old standby of shooting a bunch of groups and picking the one that looks the best.</div></div>

I believe the OCW website says you should pick the three groups that are closest in distance and placement from the center, it really doesn't have to do with group size.

From the OCW site...

14. Triangulate the groups. This means to connect all three shots in a triangular form, and determine the center of the group, and plot that point on the target. Measure this point's distance and direction from the bullseye, and record the information somewhere on the target. Do this for all of the targets. If you have a called flyer, you should discount that shot, or replace it in the group if you have an additional round loaded with that charge.

15. You will now look for the three groups which come the closest to hitting the same POI (point of impact) on the targets. The trend of the groups should be obvious, normally going from low and favoring one side, to high and favoring the other side. But along the progression, there should be a string of at least three groups that all hit the target in the same relative point.

16. After you have carefully measured group sizes and distances and directions from the bullseye, you will know which three groups come the closest to hitting the target in the same POI. You now choose the powder charge which represents the center of this string. For example, if 34.7, 35.0, and 35.3 grains all grouped about 1.5 inches high, and about 3/4 of an inch right of the bullseye, you would choose the 35.0 grain charge as your OCW (optimal charge weight). This charge will allow 34.7 and 35.3 grain charges to group right with it. This will be a very "pressure tolerant" or "resilient" load.

17. Remember, don't get "bowled over" by a tiny group which falls outside the OCW zone.
 
Re: OCW help...168 and 175 grain

You didn't mention any wind?

For the 168's the 44.7 gr load might hold as much promise as the 45. Doesn't appear to have much, if any, vertical spread. The horizontal spread could be wind or shooter.

The only thing I don't like about the "round robin" shooting is that you have to move from target to target. Slight changes in your position can impart enough differences in POI to make it difficult to evaluate a load.

My OCW development targets looked similar but I found the best results by selecting the load with the least vertical spread and then working with length.
 
Re: OCW help...168 and 175 grain

I thought about the 44.7 load as well. Wind was calm that day thought but it could have been me that was causing the spread. I thinking I am going to try 44.1 44.2 44.3 44.4 44.5 for 175 and 44.8 44.9 45 45.1 45.2 with 168. I should be able to find them if the nodes are in these ranges.
 
Re: OCW help...168 and 175 grain

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pwizl</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: groovinpickle</div><div class="ubbcode-body">By the OCW method, shouldn't you mark the center of each three shot group and compare <span style="font-style: italic">that</span> point among the targets? Otherwise I'm not sure how your method is any different from the old standby of shooting a bunch of groups and picking the one that looks the best.</div></div>

I believe the OCW website says you should pick the three groups that are closest in distance and placement from the center, it really doesn't have to do with group size.

From the OCW site...

14. Triangulate the groups. This means to connect all three shots in a triangular form, and determine the center of the group, and plot that point on the target. Measure this point's distance and direction from the bullseye, and record the information somewhere on the target. Do this for all of the targets. If you have a called flyer, you should discount that shot, or replace it in the group if you have an additional round loaded with that charge.
</div></div>
Right, this is the step (#14) that hasn't been done. The OP needs to find the triangulated center of each of the groups and mark those on the targets, and then compare that point among targets. It's a whole lot easier to visualize that way than by just guessing looking at 24 shots spread over 8 targets.