OCW thoughts....

[Kampfjager]

I know the feeling, it's easy to become obsessed with it. A group or ES could likely always be improved, it's just a matter of when we say that it's good enough for it's intended use. I rely heavily on my Oehler for load all but I need to see a groups vertical spread to align with the chrono before I settle on it. Not sure where I read it at, it may be in the OCW write up on Mr Dan's site but I like having a charge weight that shoots similar to its next charges tested and that makes me feel like there is some wiggle room with the barrel harmonics not being extremely sensitive at that weight.

Exactly! Now with my 338LM I'll actually do an OCW at 200-250y to get the best from both modes of tests....

 

[Kampfjager]

I'm curious as to what folks are truly referring to these days when they refer to OCW.

Perhaps it is implied in everyones' posts, but Dan Newberry (creator of OCW) has always emphasized POI group centers and measuring shift of this POI center from group to group. I have not seen these measurements or points references in this thread. (aside from Plowboy85 above)

OP—can you mark the POI group centers of each group and repost the photo then? That should be telling.

Yes sir,

 

[Kampfjager]

I opologize for it being sideways, but I think you'll find what your looking for

 

[Kampfjager]

Note, the ES surrounding 45.9 is actually very very good.... its 11fps between 45.7 & 46.1

 

[Plowboy85]

Yes sir,View attachment 194070

So I eyeballed the 45.7, 45.9 & 46.1 but after you have lined them out it still seams the better charge. They are a touch left and appear to be in the some vertical range while having a tight ES and overall close velocity average amongst the 3 groups.

 

[Kampfjager]

So I eyeballed the 45.7, 45.9 & 46.1 but after you have lined them out it still seams the better charge. They are a touch left and appear to be in the some vertical range while having a tight ES and overall close velocity average amongst the 3 groups.

That's my line of thinking also, I really think that's where the OCW will fall.... there will definitely be a follow up posted in this post of just those 3 charges together....

 

[Plowboy85]

Are you planning to stretch it out to maybe 300 or so And maybe go to 5 shot groups on your follow up to help expand the margin of error? As with most of us that have full customs and some high performing factory guns the POI difference isn't always noticeable enough at 100 but the weather and us are usually a tame factor at that distance.

 

[Kampfjager]

Are you planning to stretch it out to maybe 300 or so And maybe go to 5 shot groups on your follow up to help expand the margin of error? As with most of us that have full customs and some high performing factory guns the POI difference isn't always noticeable enough at 100 but the weather and us are usually a tame factor at that distance.

Absolutely, once the OCW is confirmed i will shoot a couple 5 shot groups at 300y and also list the variables in which they were shot.... and bare in mind this is a 100% factory rifle and I'm not so delusional to think it's a one ragged hole shooter...

 

[GW Hunter]

which target alignment is correct? 2 rows of 4? or 4 rows of 2?

 

[Kampfjager]

which target alignment is correct? 2 rows of 4? or 4 rows of 2?

2 rows of 4

 

[John Polk]

I have read through all the post carefully and I find the abbreviations to be quite confusing. I'm sure this is my ignorance showing, but, unfortunately, it's my ignorance and I can't do anything about it unless I get some help. When you're writing these posts could you at least define what you're saying the 1st time you make an abbreviation so that we can all follow exactly what you mean? Thanks

 

[Kampfjager]

I have read through all the post carefully and I find the abbreviations to be quite confusing. I'm sure this is my ignorance showing, but, unfortunately, it's my ignorance and I can't do anything about it unless I get some help. When you're writing these posts could you at least define what you're saying the 1st time you make an abbreviation so that we can all follow exactly what you mean? Thanks

OCW = optimum charge weight
ES= extreme spread, lowest to highest fps in velocity....
POI= point of impact
What others can I help ya with?

 

[John Polk]

OCW = optimum charge weight
ES= extreme spread, lowest to highest fps in velocity....
POI= point of impact
What others can I help ya with?

I don't think so. Very helpful, thank you very much.

 

[new2mud]

Yes sir,View attachment 194070

For OCW you also want the horizontal average of the group—so you would wind up with a single point (x,y) for each group. Then we look at minimal shift between consecutive charges —not just vertical. Perhaps mark a red dot for the (x,y) center of each group.

I like that you have lots of data on that sheet. If we were to analyze it using the Satterlee method, then you could just focus on 45.8-45.9 due to the minimal velocity gain and then move on to seating depth.