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- Thread starter cstmwrks
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Re: If you did your OCW right ...
Interesting. I've been told and currently experiencing the OCW for myself. Find a load, then play with seating depth, which you have done. Did you weigh any of the non-bulk bullets?
Interesting. I've been told and currently experiencing the OCW for myself. Find a load, then play with seating depth, which you have done. Did you weigh any of the non-bulk bullets?
Re: If you did your OCW right ...
i wouldn't think the little bit of bullet difference would change your load that much at all. you are mainly testing pressure curves and that small of a difference in bullet will not have an affect on that.
i wouldn't think the little bit of bullet difference would change your load that much at all. you are mainly testing pressure curves and that small of a difference in bullet will not have an affect on that.
Re: If you did your OCW right ...
Same lot number bullets or different lot number? It could be that the physical shape of the bullet is slightly different so maybe need a different seating depth? Big temperature swing?
Same lot number bullets or different lot number? It could be that the physical shape of the bullet is slightly different so maybe need a different seating depth? Big temperature swing?
Re: If you did your OCW right ...
I think it's more likely the seating depth than the .5gr weight difference at 100 yards.
In my limited experience I've seen .010" change in seating depth make significant difference in accuracy.
According to newberry, a properly identified ocw will be able to with stand small changes in seating depth. I don't recall what he defined as a small change in seating depth. To me .005-.010" doesn't count as a small change. Less than .005" I would buy as a small change in seating depth. This just my limit, not a hard fast rule by any means.
Do you have any pics of your ocw test??
I think it's more likely the seating depth than the .5gr weight difference at 100 yards.
In my limited experience I've seen .010" change in seating depth make significant difference in accuracy.
According to newberry, a properly identified ocw will be able to with stand small changes in seating depth. I don't recall what he defined as a small change in seating depth. To me .005-.010" doesn't count as a small change. Less than .005" I would buy as a small change in seating depth. This just my limit, not a hard fast rule by any means.
Do you have any pics of your ocw test??
Re: If you did your OCW right ...
If your original batch of bullets was 168gn, and the new 'bulk' batch (same manufacturer, same model) really is 169gn - not a scale zero problem or something simple like that - I'd either send those dang things back to the manufacturer or find a brand with better quality control.
If your original batch of bullets was 168gn, and the new 'bulk' batch (same manufacturer, same model) really is 169gn - not a scale zero problem or something simple like that - I'd either send those dang things back to the manufacturer or find a brand with better quality control.
Re: If you did your OCW right ...
I think you are overinterpreting your groups. A 'real' OCW is a load recipie that is 'maximally' insensitive to load varriations; be that bullet weight, charge weight, seating depth, ...
There seems to be a significant change in the center of the group at '9' on the first chart. This is tryinig to tell you something.
It is my guess that if your first set of groups had 5 shots in each group, that you very well would have choosen a different group as your OCW. So why not repeat the experiment with 5 shot groups and then post the new target.
I think you are overinterpreting your groups. A 'real' OCW is a load recipie that is 'maximally' insensitive to load varriations; be that bullet weight, charge weight, seating depth, ...
There seems to be a significant change in the center of the group at '9' on the first chart. This is tryinig to tell you something.
It is my guess that if your first set of groups had 5 shots in each group, that you very well would have choosen a different group as your OCW. So why not repeat the experiment with 5 shot groups and then post the new target.
Re: If you did your OCW right ...
Seating bullets deeper into the case takes up case capacity and increases pressure and velocity. The same can be done with increasing your powder charge. Both of these have their limits before you start seeing pressure signs or loss of accuracy or both.
My personal preference is to start with finding a good powder charge and adjust seating depth in .005" increments.
You're final load should be at least tolerable of .2gr difference in powder charge. Meaning it should still hold MOA +/- .2gr.
FWIW Anytime I change lots of anything, powder, primer or bullets, I reconfirm my ocw. I don't necessarily go through the whole process, but I do load above and below my selected charge weight to confirm my accuracy node as well as shoot over the chrony to make sure it's still the same. If the node is not the same I go and redo the test. It's not hard to do and it's still trigger time.
Seating bullets deeper into the case takes up case capacity and increases pressure and velocity. The same can be done with increasing your powder charge. Both of these have their limits before you start seeing pressure signs or loss of accuracy or both.
My personal preference is to start with finding a good powder charge and adjust seating depth in .005" increments.
You're final load should be at least tolerable of .2gr difference in powder charge. Meaning it should still hold MOA +/- .2gr.
FWIW Anytime I change lots of anything, powder, primer or bullets, I reconfirm my ocw. I don't necessarily go through the whole process, but I do load above and below my selected charge weight to confirm my accuracy node as well as shoot over the chrony to make sure it's still the same. If the node is not the same I go and redo the test. It's not hard to do and it's still trigger time.
