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Fast cartridge vs slower cartridge


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Some good input on this thread, and much of it based on sound theory but patterns have far more than  velocity effecting them. Setting aside all  other aspects for a moment and think about the way the cartridge makes velocity looking at pressures which by themselves are not indicative of velocity or pattern, but more importantly how these pressures are generated  and then go about creating velocity and ultimately how this translates to the  pattern performance needs to be taken into consideration.  

Speed  fast or slow alone is no indicator of  good or bad  performance in  a  load and equally so higher or lower pressures, but what does warrant more consideration is details of the load , and just one such detail is primer selection this aspect can cause problems with pattern and effect far more than velocity on its own.

http://www.armbrust.acf2.org/primersubs.htm

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On 18/12/2017 at 19:42, neutron619 said:

As did I for the first part, but, regarding the second part - isn't "two choke sizes" a bit arbitrary? I mean, don't get me wrong - I know what you're aiming at - about 15% difference in percentage performance - but "modified" to "full" is 10% and "cylinder" to "modified" is 20%, so we should probably say what we mean.

After that, I'm afraid I disagree with hamster.

I have some evidence (albeit not enough to be comfortable resting on it at this point) to prove it, too, with more on the way just as soon as cookoff and I actually get round to producing it early next year. I always expect surprises when pattern testing, but I'm pretty confident on this one. Speed kills patterns and the smaller the bore, the harder it kills them(!).

I'm not sure where all the evidence hamster is quoting is, but I haven't seen it in what is now quite a lot of years of looking into the subject. Aside from the direct comparison I've done between the Hull Subsonic and Sovereign cartridges, which showed a 12-15% advantage to the subsonic cartridge in spite of the fact that the components of the Sovereigns are newer, better made, and include much harder shot, about whose advantage to percentage performance there is little doubt, I have over a year's worth of .410 patterning data that shows that the slower the cartridge, the better it patterns, almost without exception. Of course, no two shells are comparable (except in .410, they occasionally are, as they're basically the same recipe with different quantities of powder, made by one producer for different "manufacturers") but there is too much evidence pointing to the damaging consequences of speed for me to simply ignore it.

Apart form anything else, as I've twice shown here on previous occasions, with mathematical proof, the faster the shot goes, the harder it hits the choke surface and the more it deforms, so unless anyone wants to argue that shot spread and loss of charge are not caused, at least in part, by pellet deformation (good luck with that one) then there is no scientific way one can prove that higher velocity is advantageous. What I will be wanting to know, if anyone tries, is what on earth mitigates this increased damage, if they truly believe smashing the pellets together and into the barrel wall harder is going to create better patterns. It's just not credible.

I replied to hamster because I knew what he was getting at. Similarly, by the look of it, you also grasped what I was saying - as probably did everyone else who's following this. To avoid the arbitrary figures, those for TC need defining.

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14 hours ago, Fen tiger said:

Some good input on this thread, and much of it based on sound theory but patterns have far more than  velocity effecting them. Setting aside all  other aspects for a moment and think about the way the cartridge makes velocity looking at pressures which by themselves are not indicative of velocity or pattern, but more importantly how these pressures are generated  and then go about creating velocity and ultimately how this translates to the  pattern performance needs to be taken into consideration.  

Speed  fast or slow alone is no indicator of  good or bad  performance in  a  load and equally so higher or lower pressures, but what does warrant more consideration is details of the load , and just one such detail is primer selection this aspect can cause problems with pattern and effect far more than velocity on its own.

http://www.armbrust.acf2.org/primersubs.htm

Good point which opens up another aspect of patterns which has not yet been mentioned on this thread - that of balling.

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Guest cookoff013

guys.

i am really interested in the first 1" in a chamber. after that, i am not really interested. there was a patterning project i am thinking about with Neutron,

i cant see how a single primer change can cause the differences that would cause -effect of patterning, same as pressures, i`ve enough pressure data to know  that pressure varies, shell to shell. some pass average, some have low pressure, some have medium pressures but fail cip sn2 pressure variation and  are valid reloads that is published, and used. 

there are other factors that change patterns, wad, shot, barrel, speed, size, choke, restriction, etc, these all are not the single entity that is the cure all end all to the patterning question.

when i do a patterning assay i`ve asked quite a lot of questions as to what we can do to make a sensible conclusion. because i dont want to eventually say, cartridges should only be shot on a sunday afternoon, about 3 minuits from midday, for the best patterns.

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