islandgun Posted November 22, 2014 Report Share Posted November 22, 2014 . From "The Modern Shotgun Volume 2 - The Cartridge" By Major Sir Gerald Burrard Bt,, D.S.O., R.F.A (retired) = old book published 1955 Page 145 Factors Affecting Pressure There are various factors which affect the pressure developed in a shotgun cartridge, some of which are obvious and some of which may not be, but all of which should be realised. Shot Charge. The first of these is the weight of the shot charge, and this is one of the obvious ones,...................... Size of shot. Owing to the large number of pellets, very small shot sets up more friction on the sides of the bore and offers more resistance to movement. This results in a higher pressure. In the same way a few pellets of a very large shot are comparatively easy to move, and so the pressure is reduced. In actual practice there is little difference between the 1-inch pressure when cartridges are loaded with ordinary sizes, such as from No.4 to No.7. But No.9, for example, would result in quite a noticeable higher pressure being developed than by a very large size such as BB. The book is old but the principle still applies? The author was well respected - if you see a copy buy it. If smaller pellets fill all the voids, then in effect and taken to its illogical conclusion and given small enough shot it will become a solid object which then would make the last sentence about BB untrue Quote Link to comment Share on other sites More sharing options...
rbrowning2 Posted November 22, 2014 Report Share Posted November 22, 2014 . If smaller pellets fill all the voids, then in effect and taken to its illogical conclusion and given small enough shot it will become a solid object which then would make the last sentence about BB untrue Like your thinking, but it's not calculus and the "flow" movement of individual pellets will always be different from the flow of a single solid homogeneous mass. Quote Link to comment Share on other sites More sharing options...
Guest cookoff013 Posted November 22, 2014 Report Share Posted November 22, 2014 Having 2 degrees is not "data" based evidence. Data is. Having data from the 50s isn't relevant to modern loads. Data probably derived from lead crusher and inaccurate chronos. I bet most plastic wads were designed and made in the late 70s some 1/5th a century later. I havent even mentioned powder yet. That's a minefield. Quote Link to comment Share on other sites More sharing options...
grrclark Posted November 22, 2014 Report Share Posted November 22, 2014 (edited) If smaller pellets fill all the voids, then in effect and taken to its illogical conclusion and given small enough shot it will become a solid object which then would make the last sentence about BB untrue It it is a solid object and smaller in outside diameter than the barrels inside diameter then it would pass with little friction. As the small shot size load is effectively fluid it would expand to fill the inner dimension of the barrel and have a greater surface area in contact with the barrel, hence greater friction. If it is a shot cup then effectively it would work as a solid object. I would contest that if in a shot cup the dimension of the shot is of no relevance. Edited November 22, 2014 by grrclark Quote Link to comment Share on other sites More sharing options...
rbrowning2 Posted November 22, 2014 Report Share Posted November 22, 2014 (edited) Having 2 degrees is not "data" based evidence. Data is. Having data from the 50s isn't relevant to modern loads. Data probably derived from lead crusher and inaccurate chronos. I bet most plastic wads were designed and made in the late 70s some 1/5th a century later. I havent even mentioned powder yet. That's a minefield. Beg to differ very little basic principles have changed over the year and for fibre wad cartridges nothing has changed (yes we may have better powder and primer) but you still have Boyle's laws to live with. Yes the plastic cup wad should widen the cap in shot sizes but a difference should still be measurable. Yes modern ballistic methods may be able to resolve the pressure more accurately but the lead crusher done a good job of measuring relative peak pressure. As for velocity have you seen how it was measured then? They were measuring time to six decimal places even then and over a greater distance to ensure accuracy. Would be a very interesting project to repeat the findings if one had the modern ballistic gear available. . Edited November 22, 2014 by rbrowning2 Quote Link to comment Share on other sites More sharing options...
rbrowning2 Posted November 22, 2014 Report Share Posted November 22, 2014 If it is a shot cup then effectively it would work as a solid object. I would contest that if in a shot cup the dimension of the shot is of no relevance. You may be correct, would be good to have the ballistic gear to prove it. Quote Link to comment Share on other sites More sharing options...
grrclark Posted November 22, 2014 Report Share Posted November 22, 2014 You may be correct, would be good to have the ballistic gear to prove it. I'm hypothesising certainly, but providing the shot cup is sufficiently rigid to contain any lateral expansion of the shot as it overcomes its initial moment of inertia into a linear movement then it really should act the same way whether it is #5 shot in the cup or #9. I accept that with unconfined shot propelled in front of a shot card and fibre wad the behaviour of #5 or #9 shot would be different. Quote Link to comment Share on other sites More sharing options...
biketestace Posted November 22, 2014 Report Share Posted November 22, 2014 Cook, 1st - How do I make the perfect pancake ? 2nd - Whats the best batter mix ? 3rd - Sod that, Lets get talking powder........... Quote Link to comment Share on other sites More sharing options...
Guest cookoff013 Posted November 22, 2014 Report Share Posted November 22, 2014 Powder? Or application of powder? Quote Link to comment Share on other sites More sharing options...
biketestace Posted November 22, 2014 Report Share Posted November 22, 2014 Application please, then powder, Be gentle Quote Link to comment Share on other sites More sharing options...
Guest cookoff013 Posted November 22, 2014 Report Share Posted November 22, 2014 Application please, then powder, Be gentle Sounds like you need baby powder. Quote Link to comment Share on other sites More sharing options...
biketestace Posted November 22, 2014 Report Share Posted November 22, 2014 Quote Link to comment Share on other sites More sharing options...
roughshooter Posted November 22, 2014 Report Share Posted November 22, 2014 Sigh....... I remember when loading was fun Quote Link to comment Share on other sites More sharing options...
biketestace Posted November 22, 2014 Report Share Posted November 22, 2014 SPOT ON ! Quote Link to comment Share on other sites More sharing options...
Continental Shooter Posted November 22, 2014 Report Share Posted November 22, 2014 Having 2 degrees is not "data" based evidence. Data is. Having data from the 50s isn't relevant to modern loads. Data probably derived from lead crusher and inaccurate chronos. I bet most plastic wads were designed and made in the late 70s some 1/5th a century later. I havent even mentioned powder yet. That's a minefield. It probably isn't data based evidence, but definately gives you the tools to understand and interpret it in a much deeper and accurate manner!! Ballistics is broken down into four categories Internal ballistics: Thermodynamic & Dynamic and more specifically Motion regulates this part Transition ballistics: Dynamic and specifically Acceleration owns this part External ballistics: It's Fluid Dynamic time!! Terminal ballistics: here's a mess!! Mechanic, Thermodynamic, and few more... I am afraid to say that despite 2000-2300 years of studying and progresses ... these physical lows still stand and are at the base of anything we use or do today! Just for clarity, my data is from a Paini D-30 which is re-calibrated every year. Quote Link to comment Share on other sites More sharing options...
rbrowning2 Posted November 23, 2014 Report Share Posted November 23, 2014 Just for clarity, my data is from a Paini D-30 which is re-calibrated every year. Nice, you have the test gear to provide the data to support a lot of yours and other posters ideas, is it with you in the UK? if so I am sure the PW members can keep you busy with some testing and busting some myths. . Quote Link to comment Share on other sites More sharing options...
Continental Shooter Posted November 23, 2014 Report Share Posted November 23, 2014 yeah, it's very nice and accurate machine.... it costed me 30 K new with all the transducers, software, etc and nope, it's not with me because i don't know where i can store it and use it safely. I travel quite a lot for work and research and, whilst in Italy i have my own 'bunker' where i can keep it, here i wouldn't even know where to find a similar structure to hold the whole thing (shot diverter, collection pool, measuring station including shot proofed glass and that's not including the instruments for measuring pressure and speed). when i am here (so, most of the time in the past few years) i use the Birmingham proofing house for my special loads (semi magnum & magnums) for the everyday shell, you'll allow me, i don't quite need it for the powder i use (Sipe, Tecna and 800x), however, i used it recently to gauge the vivacity of an A1 batch i bought off C&G just to make sure it was similar to the one i had before (which it wasn't) then to re-proof the new shell i assembled to see if it matched the previous one! For now, my baby is in the safe and capable hands of a gunsmith friend of mine who has a gun shop (and in Italy nearly every gun shop reloads and sell its own cartridges) where it's been maintained and provides me with an income (i rent it out at 750 Euro a month/1000 shells + maintenance). I know people would like to have one handy, and if I could find a safe place to store it and someone to transport it i would take it over .... but for now i couldn't find anyone in Italy that could even help me to transfer my shotguns over...never mind such a fragile piece of equipment... Quote Link to comment Share on other sites More sharing options...
Continental Shooter Posted November 23, 2014 Report Share Posted November 23, 2014 PS: if it doesn't involve US powders which are nearly impossible to find in Italy, and having the exact components, i could probably ask my friend to test some shell for people... if the project is worth it (not an everyday pigeon shell)! Quote Link to comment Share on other sites More sharing options...
clayboster Posted December 2, 2014 Report Share Posted December 2, 2014 had a zabala cardiener 3 1/2 inch with a double discharging facility 2 1/4 oz in each barrel ! very frightening 4 1/2 oz of 6 shot going down range out of a 12g peppered don't come in to it LOL. ouch...4 1/2 oz in one go!!, my shouder hurts just thinking about it, shot a friends 4g with 3.5 oz earlier this year... needs thering to a punt. ! Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.