wymberley Posted February 17, 2017 Report Share Posted February 17, 2017 Didn't want to side track, 'which to change first, cartridges or chokes' in 'guns and equip.' where 'observed velocity' was mentioned My step-son has just started shotgunning and I was looking at a way to give him a guide as per the Title for different cartridges without carrying Vol 2 of Burrard around in his back pocket. Because of the known problems regarding the calculation of shotgun MVs, it involved a bit of a fiddle. However, starting with the observed velocity and adjusting the ballistics programme for the 3 yard figure I finally got some sense out of it. For a novice shooter who's not quite sure what is what but who wants some idea, then if you take the Cartridge Velocity Level (these two figures given, 1070 and 1120 ft/sec, are known as the "observed velocity" and relate to the old method of defining cartridge pellet speed) figures in the relevant tables in the Eley diary, it'll give you some idea. For cartridges with a given velocity of between 1300 and 1400 ft/sec use the table for 1070 and similarly, for 1400 to 1500, the 1120 table. Now, this will not be totally accurate but more so than a novice's ability to judge range and sufficient to keep one out of trouble. Quote Link to comment Share on other sites More sharing options...
figgy Posted February 18, 2017 Report Share Posted February 18, 2017 Is this to work out time it takes shot to travel to target at xy or z range? To work out forward allowance? Or am I on a totally different plane. Because if that the case then target flight speed needs to be a known for it to work on the vector. Quote Link to comment Share on other sites More sharing options...
wymberley Posted February 18, 2017 Author Report Share Posted February 18, 2017 (edited) Is this to work out time it takes shot to travel to target at xy or z range? To work out forward allowance? Or am I on a totally different plane. Because if that the case then target flight speed needs to be a known for it to work on the vector. Good lord, you've lost me. The tables in the diary relate to down range energy/velocity for differing shot sizes. The range of velocities/shot sizes available are legion and I was just trying to give a starting point for a reasonably accurate assessment on which to base a decision on their effective range for any given species. Although the quoted velocity in the thread referred to was quite slow, I don't think that too many of the younger generation realise that a No 7, for example, with a observed velocity of 1200 ft/sec was cracking on at some 1600 at the muzzle. Edited February 18, 2017 by wymberley Quote Link to comment Share on other sites More sharing options...
figgy Posted February 18, 2017 Report Share Posted February 18, 2017 I see I was on a different track, I was thinking down range velocity helping with forward allowance for beginners. Quote Link to comment Share on other sites More sharing options...
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