spandit Posted May 2, 2015 Report Share Posted May 2, 2015 Free to use, hope someone might find it useful: http://www.creffield.com/ballistics/target.php On loading the page, a random set of 10 shots is generated at a default 50 yards (.224" calibre - changing this only alters the hole sizes drawn on clicking "calculate"). If you don't have the genuine measurements from your target, you will have to scan/photograph the target in and load into a paint/CAD programme. Once you have determined the coordinates of each shot (by drawing a circle round each one and finding the centre), you can enter a value in the top box that equates to the dimension of a known inch (i.e. if your scanned target is 2 inches across, measure this and divide by 2) The group size is given in three ways. The more meaningful is the 2 x mean radius (which is calculated by averaging the distance of each shot from the average position of all shots - indicated by a red cross) as this isn't so distorted by the odd flyer. The extreme spread works out the maximum distance between any two shots. The diagonal gives the diagonal measurement of a rectangle surrounding all shots (using centre of the shots) It's only 537 lines of code! Quote Link to comment Share on other sites More sharing options...
10gaugewannabee Posted May 3, 2015 Report Share Posted May 3, 2015 cheers , will look at it later Quote Link to comment Share on other sites More sharing options...
dadioles Posted May 3, 2015 Report Share Posted May 3, 2015 I use a nice bit of software called "On Target Precision Calculator" written by a really nice chap called Jeffrey Block in USA. There is a freeware version as well as a paid for version (only £10). If you have reasonable ability with a computer and enjoy playing with software you will love this. Input is from a camera or (better) a scanner. It is very accurate. Quote Link to comment Share on other sites More sharing options...
spandit Posted May 4, 2015 Author Report Share Posted May 4, 2015 Just updated it to give a few more options (and correct the extreme spread calculation error): http://www.creffield.com/ballistics/target.php Quote Link to comment Share on other sites More sharing options...
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