View Full Version : anybody use?
01-12-2005, 02:20 PM
a custom BDC from kenton industries or a like company? any input? They seem to me that if you have a good repeatable scope, they would be the fastest, simplest route to go until you get beyond 1200 yds or so.
01-12-2005, 04:10 PM
The knobs are calibrated for one set of conditions.They would work fine until you change alt,or temp or bar pressure.....If you used one set of knobs for all conditions.You would just be guessing
01-12-2005, 06:05 PM
I under stand that but it would only mean an 80 dollar knob for different elevations, maybe one for summer and one for winter for the 2 differnt elevations I hunt in, How much difference does barometric pressure make?
01-12-2005, 07:16 PM
I under stand that but it would only mean an 80 dollar knob for different elevations, Why spend the 80 bucks when you can make a chart from a free ballistics program.Print it out on a half cent piece of paper and cover it with 3 cents of laminating sheets :D ...You can do it the way you want.....I'm just trying to tell you what works and what does'nt....How much difference does barometric pressure make? Alone not much.Add it into a 20 degree temp difference and a few 1000 feet in eleavation and You just missed...Its not bad until you get out past 700 yards or so.....Just trying to help
01-12-2005, 08:27 PM
ok I got plenty of ballistic programs but what do I do check temp, bar. pressure every day and print out a sheet everyday? How do you do it? I'm trying to learn here, how much change in say just bar pressure does it take to effect POI, I know that ambient temp has a pretty big effect, that I figured I could work around by doing my bench work at about the average temp for deer hunting in this area. I only shift around 1200 feet in elevation wherever I go.
01-15-2005, 05:11 PM
In the name of "KISS", I can suggest doing as the Swedish army and use both Ridgerunner and Boyds approaches.
Set up a BDC calibrated for standard atmosphere (SAC).
Use a Silva weathermeter or similar and measure pressure/temperature/ wind, look in the datatables and add/substract pre-calculated values based on the measured deviation from SAC.
Works vey well, even when you're getting tired and stupid. Put up a "fill-in-the-blanks" chart and you can doublecheck your calculations should you miss. But you are looking at $80 for your ring and $150 for the weatherstation!
01-17-2005, 10:20 AM
I don't create a new chart for everyday, but infact have combined several sequences to form one chart for where I typically hunt. (different wind speeds for drift for example)
My chart is based on 1200ft above sea level for example. That, and 35 deg. with std barometric pressure at that elev. and temp. That's not exactly what I see everyday where and when we hunt, but it's close enough, determined through experience. In the summer when temp climbs, my chart is off ( I always shoot high). I could develop a new one for the temp, but I just shoot the first shot over and adjust from there.
If I was going out west and hunting at say roughly 8500 ft. I would definately want to do a new chart for that elevation. As Boyd said: most of this won't affect you that much under 700yds but any one of these things can put you over or under a deer at 1000. Believe it or not, there is an Exbal program to load on your PDF and develop an "exact" drop for the current conditions. Granted you have the ability to determine them. People are making 1st shot kills to extreme ranges using it. Kestrel makes great instruments for determining wind speed, temp, pressure, etc.
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