1290 wrote:I have worked out a measure of how 'overbore' each chambering is, let it be known as the 'B factor'
Chronos wrote:Maybe you need to dumb it down a little more for me 1290
I admire your work, you've spent a fair bit of time putting it together.
The b factor is a value but what does it mean in the real world and how might it be applied to measuring efficiency, barrel life etc?
6PPC is extreamly efficient but barrel life is shorter than .223 due to throat erosion.
How might shoulder angle or powder speed and volume influence or even barrel length effect cartridge choice?
It certainly is a can of worms eh?
Chronos
Lorgar wrote:Had a bit of free time this weekend did ya?
Interesting though, lets see if the name sticks and you've officially coined a phrase
1290 wrote:Chronos wrote:Maybe you need to dumb it down a little more for me 1290
I admire your work, you've spent a fair bit of time putting it together.
The b factor is a value but what does it mean in the real world and how might it be applied to measuring efficiency, barrel life etc?
6PPC is extreamly efficient but barrel life is shorter than .223 due to throat erosion.
How might shoulder angle or powder speed and volume influence or even barrel length effect cartridge choice?
It certainly is a can of worms eh?
Chronos
Chrony, I could get into a heck of a great deal more technical... send you guys nuts, how far down do I need to dumb it??
100 good
120 gooder
150 even gooderer
200 rule goodest but.
1290 wrote:Chrony, you seem generally switched on enough to work out what it means.....No not necessarily better, it works off a datum, a reference point if you like, being the ratio of volume to bore of the 223, as 'bore'.... its not meant to measure the perfect round or the best but give YOU a standardised measure, what you do with the information is up to you. You can see the PPC is under the 223Rem, so if you like mid-range/mid-potency target rounds it will help You to say, find an equivalent 30cal....
The only assumption is that you can interpret what bore/overbore means relative to a predetermined value/standard...the 223Rem...... if not, sorry, this isnt for you.....
Trekin, it took you 5 days to have a go at at my attempt to add something.... good going...
What/where is this formula that I have plagiarised? I'm well aware that the ratio of volume to bore diameter is a standard consideration, in this form I have never come across, at least not when I sit around the camp fire chewing the tobacci with all those wildcatters that I associate with...
Oh, dont think up another measure of distance, its been done before. What is this metre you speak of? Its not necessary, we have the chain.. Do you know what that is? (off to google )
1290 wrote:By all means, 'peer review' away... but its not an academic paper.. i've done this more so to generate some discussion about the subject, not so much the method to derive it, but thats fine; in the first post I described the following;
It is simply, a calculation considering the gross case volume, not net volume as the thickness across the case could only be assumed, the external measurements are standardised............ considered RELATIVE to the area where the gasses and bullet leave the case....factored by 100 to give you a percentage relative to the unity (223Rem) simple.... really. Consider the 223 Rem has a B factor of 100 (remember that).
- that is 'gross case volume' and why? Gross is the total without deductions, outside measurement because that is the only standardised measurement available.
The description of how its done is enough. Had I included the full calculation I'm sure most readers would develop some instant psychological response..... but please have a go at just the volume part of it, the alpha numerics are the many case dimensions as provided by CIP;
=IF(X324=0;IF(Q324=0;(PI()*(1/3000)*(I324-N324)*(((W324/2)^2)+((AL324/2)^2)+0.25*AL324*W324));(PI()*(1/3000)*(I324-Q324)*(((W324/2)^2)+((AL324/2)^2)+0.25*AL324*W324)));IF(Q324=0;(PI()*(1/3000)*(((G324-N324)*(((W324/2)^2)+((X324/2)^2)+0.25*X324*W324))+((H324-G324)*(((AK324/2)^2)+((X324/2)^2)+0.25*X324*AK324))+((I324-H324)*(((AK324/2)^2)+((AL324/2)^2)+0.25*AL324*AK324))));(PI()*(1/3000)*(((G324-Q324)*(((W324/2)^2)+((X324/2)^2)+0.25*X324*W324))+((H324-G324)*(((AK324/2)^2)+((X324/2)^2)+0.25*X324*AK324))+((I324-H324)*(((AK324/2)^2)+((AL324/2)^2)+0.25*AL324*AK324))))))
How did you go? Do you still want to full calculation?
As far as using grains, that's a mass unit not a volume unit...I've used metric units though it doesn't matter as its a ratio, multiplied by a unitless constant.
I dont know what the 'old overbore cartridge formula standard' is, perhaps imperial units without the ratio part.... I'm not too concerned.
Why 100x? because in my experience, people find a range of numbers easier to absorb/read/consider when there is no decimal point, eg 1.82 versus 182.
The only improvement (future) I'll make to my calculation is as described initially, reduce the volume by a bore-length of bullet from the neck volume, and try to derive a deduction for brass thickness probably from the neck thickness which is a known.
Apart from that, I'm trying really hard to read into your contribution where you're being constructive. Without success. If you don't think there's any value to my work and you prefer someone else's, that is, if you prefer pictures on a graph as opposed to numbers that can be listed and sorted.... great, good luck, I'm happy... that your happy.
Now that we've unequivocally established your opposition or at least lack of interest in this body of work.....no doubt you'll no longer return to this thread, and leave this waste of effort and time to others to contemplate