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Old 29th January 2016, 06:50 PM
verminator verminator is offline
Join Date: May 2010
Member of: Bisley
Location: London
Posts: 94

Originally Posted by Brian.Samson View Post
When you quote figures in mildots like that it sounds like a lot - wow - a 1/4 of a mildot!!...

Actually a 1/4 of a mildot at 11 yards is less than half a pellet width. So if you just aimed exactly how you would have done if the target was on the level, you would hit half a pellet width high. That gives you plenty of leeway to take down a 15mm kill.
Maybe, but take the case of the 15mm kill, 45 degrees at 13 yards. It has happened before and will happen again. Knockover targets tend to stand vertical regardless of height, so this is more like looking at a 10.5mm x 15mm oval. My pellets are 5.5mm, leaving just 2.5mm wiggle room either side. I'm not so comfortable with that.

Then there are the longer shots. 20mm kills at 30 yards or 25mm at 40 yards, sometimes placed at considerable height. Through the scope, these kills look tiny. I really want to know my aim point is right.
Originally Posted by Brian.Samson View Post
The Rule of 15's will get you close enough to the correct answer never to have to worry about an angle or a mathematical model again.
The rules in HFT are continually evolving, being made harder for those top .177 shooters and doubly so for me. The .22 trajectory is at least twice as bendy and is likely to be more affected by effects of elevation. Turns out the "Rule of 15s" works quite well even for a .22 at close range, but there are subtle differences in the measured results and I want more precision. I have not been able to put targets as high as I would like, I expect the differences will get bigger the higher up they go. I like maths, what does that tell you
Originally Posted by Brian.Samson View Post
The mathematical formula for this is very complex, it's not the sort of equation you can do in your head, but if you tell me your MV and the BC of your pellet, I'll give you a spreadsheet with every angle and every range on it and tell you how much higher your pellet will hit. You can print that spreadsheet out, laminate it and carry it round with you if it makes you feel better.

Everyone else will just be using the rule of 15's and not worrying about the angle, but at least you'll stand out from the crowd.
I won't be doing this in my head. Like you I will prepare a spreadsheet to do it for me. I already calculate the path and aim points myself, hence my general disregard for Chairgun. Although I have to say Chairgun has become rather sophisticated of late.

Also, I won't be carrying around some massive table, I will analyse the numbers to spot any patterns and come up with a simplified rule probably similar to the "Rule of 15s" but tailored to my particular setup.

I have work to do for sure, taking lots of measurements, trying to factor in various measures, but I'm confident I will get there eventually. When this wind stops blowing a gale...

It has been a good thread, despite some of the less constructive comments. And you haven't heard the last of my bendy barrel either
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