You could easily waste lots of components trying to find a bad node on a 6BRA!Is there a difference between a node and a load that just shoots really good? I'm at 30.1 H4895, 105 bullets, Alpha brass 1-8t 6BRA at 2870-+ and it seems to shoot really good at 100 now to go out further when I can drive 1.5 hours to the range. ;{
thoughts?
Well Mike, been there lol.You could easily waste lots of components trying to find a bad node on a 6BRA!
That is the truth. I have seen something similar with my 6.5x47. A half a grain change will barely make a difference in accuracy. Some cartridges just don't care as much as others.You could easily waste lots of components trying to find a bad node on a 6BRA!
1. If you are already near a high-pressure value, changing 3% up can be dangerous.Mr OCW Dan Newberry states a node will repeat at 3% charge weight difference, while a scatter node is at 1.5% difference. Observing this behavior when evaluating charge weight gives credence to the results.
1. If you are already near a high-pressure value, changing 3% up can be dangerous.
2. in 18 years of running this site, and working with multiple disciplines and multiple world record holders and national champions, I believe that this Newbury statement is not useful at all and is basically not helpful for the majority of rifles and handlorders.
I could be a little more blunt, but you get the idea.
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I would also say that I believe the OCW mythology has deceived and mislead more handloaders than it has helped, by far. But I can tell you that OCW is cynically beloved by many respected barrel-markers, who have told me privately that they know people are wasting a huge amount of barrel life following OCW suggestions.
Paul, I have to agree that using a general number, such as 3%, across the board of different cartridge shapes, designs and capacities, along with varying powder characteristics is not a rule I'd follow well. And, I've never given much credence to the whole obt thing, as most people agree that it only gets ya "close." I feel like I can explain this and actually, for once, I tend to agree with his repeatability of nodes and "scatter nodes" and why there is about twice as far between "nodes and scatter nodes."...although I don't agree with the generality of 3% across the board. I'll say this...I have been able to quantify, reasonably so, the value of .3 gr of n133 in a ppc and how that increment correlates to 1 mark on my tuners. It's actually very similar to his theory but with lesser values, in this case.I won't carry this further except to say I believe the OCW observations will NOT help the vast majority of people. There are far better, more efficient, more repeatable, and more intelligent methods to achieve best accuracy with custom barrels.
I have seen people waste 100s of rounds of barrel life with this kind of OCW BS, when they could have achieved more with a .010" or 0.015" change in seating depth, or switching neck tension, or powder choice.
I will take it further, I have heard/seen/read no substantiation from ANY credible source whatsoever that a 3% change in powder weight achieves any highly predictable accuracy NODE repeat in multiple cartridge types, small, medium, and large. Additionally a 3% change is very significant, that would take you out of the known good load weights for smaller cartridges.
For example, a 30.0 grain 6mmBR Varget charge (good for 107s), increased 3% puts you at 30.9 grains. That is way too high if you are close to max with 30.0, and I don't know ANYone who would expect to duplicate accuracy going DOWN 0.9 grains from 30.0. No way.
I would also say that I believe the OCW mythology has deceived and mislead more handloaders than it has helped, by far. And I can tell you that OCW is cynically beloved by many respected barrel-markers, who have told me privately that they know people are wasting a huge amount of barrel life following OCW suggestions. They laugh and say "OCW is a great boost for replacement barrel orders".
Quite similar to my method. I'm a wildcatter I set up the lab andWith a new powder and or a new rifle the first thing that I do is to determine what the hottest load is for a given bullet with it seated into the rifling, also recording temperature and humidity. I do this by doing a one shot per load test. In cases of this size the increment for this would be .3 gr. One of the advantages of this is that if I run into a situation where I want to do a little experimenting, I know how far I can safely go.
Node: A point, line , or surface of a vibrating body or system that is free or relatively free from motion. This is Websters definition of node. The only way i have found to take advantage of this is to alter charge weight to make the bullet exit during the relatively motionless portion of the vibration cycle. However I learned to reload in day and time when jump was not even remotely considered to be beneficial. I have never intentionally jumped a bullet in my life. I am curious to find out if bullet jump can be used to change barrel dwell time to cause the bullet to get to the motionless part of the vibration cycle( node), or does it alter group size by some other means? I am not telling anybody they are wrong i am looking for information. i think that many here think a node is another word for small group or some thing like that , but I am pretty sure it means a motionless portion of the vibration cycle of the barrel and making the bullet exit in that motionless moment in time allows smaller groups. Is bullet jump another way to put the bull in the node without using a charge weight change????
I always wondered which is correct when fellas speak of the ocw sinne wave and how the optimum point is either the top of the wave or the bottom vs the middle etc. Now Ive learned to view optimum as a point of no vertical shifting of group centers ( within conditions of course) but how does that translate to the sinne wave ?
Never heard of target curve but I think im pretty clear on what positive compensation is as well as exit timing results on paper , maybe were talking about the same thing or I’m just stupid but my question is where on the sinn wave is this optimum spot ? It isn’t in the middle of the wave between the low and high because that’s not stable unless it flattened out so seemingly the top or bottom if wide enough and why would one be preferred over another as long as it’s stable ?The target curve and barrel vibration curve are different but related. Look up positive compensation and Kolbe.