Flynn Posted February 28, 2014 Report Share Posted February 28, 2014 I'm writing some software which does a few aerodynamic calculations. As I was working some figures out I got to wondering what the BC of shotgun shot is. Obviously it's going to be absolutely dire, but just how dire? All I find find online are BC tables for rifle bullets and airgun pellets and nothing for shotgun shot. Anyone know of any site where this kind of information has been determined and published? Quote Link to comment Share on other sites More sharing options...
kent Posted February 28, 2014 Report Share Posted February 28, 2014 its a little different than that when your also looking at things like spherical form etc. I should look up a good published work on the subject , I doubt its as straight forwards as it seems Quote Link to comment Share on other sites More sharing options...
Hubris Posted February 28, 2014 Report Share Posted February 28, 2014 If I remember rightly, the bc for a projectile is different at different velocities. For large fast projectiles an average is good enough for most balistic calculations. For birdshot,I wonder if the large variations in speed (ie rapid decelaration) over the expected time of flight varies the bc too much for a usefull average figure to be arrived at. Also as suggested, look for engineering articles on drag coefficients for spheres. Good luck, Quote Link to comment Share on other sites More sharing options...
Brad93 Posted February 28, 2014 Report Share Posted February 28, 2014 Ballistic coefficient is the same no matter what the velocity. It's it the ability of a projectile to overcome the air resistance upon it. Very simply: BC = Mass / (Coefficient of drag x Cross section area) Quote Link to comment Share on other sites More sharing options...
wymberley Posted February 28, 2014 Report Share Posted February 28, 2014 Yes. Wasted countless hours before Christmas on something that didn't happen. Pm your requirements on shot sizes (English) for lead, steel, bismuth and Hevishot. Quote Link to comment Share on other sites More sharing options...
Flynn Posted February 28, 2014 Author Report Share Posted February 28, 2014 Yes. Wasted countless hours before Christmas on something that didn't happen. Pm your requirements on shot sizes (English) for lead, steel, bismuth and Hevishot. Superb. PM inbound and thank you very much. Quote Link to comment Share on other sites More sharing options...
TriBsa Posted February 28, 2014 Report Share Posted February 28, 2014 (edited) Here's an article on cannonball air resistance, that might help, they being spherical too: http://arc.id.au/CannonballDrag.html Tom Edited February 28, 2014 by TriBsa Quote Link to comment Share on other sites More sharing options...
Dekers Posted February 28, 2014 Report Share Posted February 28, 2014 Good question, never given it any thought but have always considered it poor. If you actually find any figures please publish them for interest. Cheers Quote Link to comment Share on other sites More sharing options...
HW682 Posted February 28, 2014 Report Share Posted February 28, 2014 (edited) I'm writing some software which does a few aerodynamic calculations. As I was working some figures out I got to wondering what the BC of shotgun shot is. Obviously it's going to be absolutely dire, but just how dire? All I find find online are BC tables for rifle bullets and airgun pellets and nothing for shotgun shot. Anyone know of any site where this kind of information has been determined and published? I would imagine the behaviour of a pellet in a cloud of shot would be different to an individual pellet due to turbulence and slip streaming etc? However, just for interest Chairgun gives some BC figures for round pellets (using the GS model for drag), as follows (even .177 is probably too big for you): .177 0.0140 ,20 0.0150 ,22 0.0170 0,25 0.020 .308 0.033 .45 0.04 050 0.037 .354 (9mm ball) 0.03 I've no idea whether that helps or not. Edited February 28, 2014 by HW682 Quote Link to comment Share on other sites More sharing options...
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