SRGNXL Posted June 17, 2011 Report Share Posted June 17, 2011 What are your views on the following ballistic data cards? I've tried this format to 600 yards and seems to work well. It provides me with easy reference point without have many cluttered numbers. The format is widely employed by the swiss armed forces. just add or subtract the values according to the output given by your kestrel so in a 25 degrees temp and 28.05 inHg baro pressure : 8.9Mils -0.2 -0.4 =8.3 Mils elevation The values shown are for 10mph full value wind so multiply the appropriate wind value by the wind velocity in mph. Can't be simpler i guess Link to comment Share on other sites More sharing options...
MJR Posted June 17, 2011 Report Share Posted June 17, 2011 Don't understand the card? Looks like a card for 1000yds yet you used it at 600yds? Link to comment Share on other sites More sharing options...
SRGNXL Posted June 17, 2011 Author Report Share Posted June 17, 2011 Don't understand the card? Looks like a card for 1000yds yet you used it at 600yds? the one pictured is for 1000, I made others for the other distances as well. here's the one for 600 Link to comment Share on other sites More sharing options...
brown dog Posted June 17, 2011 Report Share Posted June 17, 2011 the one pictured is for 1000, I made others for the other distances as well. here's the one for 600 It's taken me some brain-ache to work out how your card is working; but now that I've got it, what you've created works in essentially the same as the way the Brit Army ASAT cards. ( I was thrown because I'm not used to seeing inHg units and I intially assumed the values to be additional Temps in DegC ) Good system. All the outputs of a PDA without the finger tapping, fragility, lack of waterproofness and battery life issues. Big thumbs up. If carrying 10 cards to cover 1000yds is what works for you to declutter the info, then all good too. One observation: Your card lists pressure as being 'barometric' but then has no 'altitude' adjustment to go with it. If you really are using the barometric value from your kestrel and then ignoring altitude, your card will be giving you 'false' outputs. If (as I suspect you may be, but simply mis-naming it) you take Station Pressure from your Kestrel (ie always treat altitude as zero) and put Station Pressure data on your card you will instantly overcome the problem - and that's exactly what I did when I was asked to improve the ASATs. Do you have an image of the Swiss Card you're able to post? Link to comment Share on other sites More sharing options...
brown dog Posted June 17, 2011 Report Share Posted June 17, 2011 Second Observation: Assuming your scope works in 0.1mRad clicks, recommend you describe all values in clicks. Right now you have your opening elevation in mils, and your corrections of the moment (ie the barometric and temp adjustments) in clicks. I then look across to the angled fire solution and see you're back to mils again. I'd recommend putting all values in 'clicks' ie, opening elevation on the 600 card is '35 clicks'. - takes the 'think' out of mixing units. Third observation: Declutter further - remove the arithmetic aide memoire that's bottom centre - I'm sure you can remember it. If you really must keep it, we read left to right (I'm assuming you're not an Arab ) do 'opening elevation' then 'pressure' then 'temp' (right now you have 'temp' then 'pressure' and that's not the order in which it's presented in your table). Fourth Observation: Move the opening elevation (having changed it to clicks! ) from the centre of your wind rose and up to the left end of your 'correction of the moment' table. Then, sticking with the 'we read left to right' principle you can get your firing elevation by simply moving your eyes left to right across the table -opening elevation (clicks)...+/- pressure correction (clicks)...+/- temp correction (clicks) ....and not have to look around the form for the various bits of data. A little more 'ergonomic' Link to comment Share on other sites More sharing options...
skany Posted June 17, 2011 Report Share Posted June 17, 2011 Fifth observation Send Bd 20 notes :-) His system is flat out the best IMHO Cheers Andy Link to comment Share on other sites More sharing options...
Orka Akinse Posted June 17, 2011 Report Share Posted June 17, 2011 +2 For the BD Cards Link to comment Share on other sites More sharing options...
brown dog Posted June 17, 2011 Report Share Posted June 17, 2011 Fifth observation Send Bd 20 notes :-) His system is flat out the best IMHO Cheers Andy Thanks Andy. - inHg and mils is about the only version I haven't built! I didn't think anyone using inHg would even look at a metric scope Have to get SRGNXL converted to millibars first Link to comment Share on other sites More sharing options...
SRGNXL Posted June 17, 2011 Author Report Share Posted June 17, 2011 +2 For the BD Cards thanks for the observations. In reality its station pressure as my kestrel's altitude is set to 0. I agree they are too cluttered especially for someone who has not used the system. I printed these in 3x2.5" sized cards and laminated them then stacked them together with a key chain as if it where a pack of cards so to say. I could perfectly use clicks only yes just to keep everything uniform. Link to comment Share on other sites More sharing options...
brown dog Posted June 17, 2011 Report Share Posted June 17, 2011 Thanks for the pic. Always interesting to see how others are tackling the same problems 2 more observations (sorry I'm being a nerd!): 1. Noticed that none of the cards indicate the pressure at which the opening elevation is correct. I can see from the table that 15degC is the opening elevation temp. Also strange to see pressure only presented as '+' values too. What about lower pressure? (I know you're only asking about table design; but in terms of computation when making the card, it's also important that you've adjusted the ballistic data to match the opening elevation's temp and pressure - and not the data shown in your top left rilfe/bullet data list). 2. In the miltary example you've posted, far far too much space is given over to the wind rose. All that space is wasted. All it's actually doing is providing a lazy-man's wind calculation for every possible permutation. There are much cleverer and concise ways of 'attacking' wind on a card. By the way, are you Swiss or is this something you've picked up along the way? Link to comment Share on other sites More sharing options...
Davy Posted June 17, 2011 Report Share Posted June 17, 2011 I like it, a nice system, I agree with BD de-clutter it, loose the math, you only need half a wind table, just split it vertically and delete the left side, I would also loose the load data top left or most of it. (I have a set of tables on the rifle at all times plus a skimmed version on my range finder and a set in my back pocket, they just say something like AI/155/metric which is enough of a title for me.) This would mean you could make the tables even smaller. I would also say convert to Mbar and keep it in clicks all round. I run a very similar load to yours in an AI and my numbers are within a click or two of the two cards shown so I guess we use the same source of base data. Also all metric or all imperial would be good, I prefer m/sec for wind but that is a personal thing. These are observations not criticisms and I have spotted a couple of things I certainly like and will probably 'borrow' for my cards. Nice! Link to comment Share on other sites More sharing options...
SRGNXL Posted June 17, 2011 Author Report Share Posted June 17, 2011 1013.25mbars if I remember well off hand is the opening pressure ie, that at sea level. the other figures show pressure decreasing and therefore an increase in altitude. the data in the top left corner of my data card was just for my records and had nothing to do with the data specifically. I had the pleasure to shoot with the swiss for a considerable time.. Link to comment Share on other sites More sharing options...
brown dog Posted June 17, 2011 Report Share Posted June 17, 2011 1013.25mbars if I remember well off hand is the opening pressure ie, that at sea level. Got it. Strange place to start though; rather like starting the opening elevation at 0 DegC and having all temp values positive. If 15degC is thought to be a good middle of the range temp, would also make sense to pick the chart pressure in the middle of where you expect your operating pressure range to lie. the other figures show pressure decreasing and therefore an increase in altitude. It's not showing increasing altitude if you're using station pressure, its just showing decreasing pressure As Davy said, I like the card - not quite how I do it, but it isn't mine and this is all meant helpfully ...even though you've made us all sound thick by editing an explanation of the card into the first post! Link to comment Share on other sites More sharing options...
.jpg.0972b4e2bdf0b5a4109eb96f2b1b62ad.jpg)
(200x135).jpg.0fd0a94f065c6cb243fdff1b40e0819a.jpg)
Recommended Posts
Archived
This topic is now archived and is closed to further replies.