Originally Posted by Sniperdad
I have started to use a kesrtal 4500 weather device and the only stats I use is the Density Altitude(DA) , which is a calculation of the effect of Temp. and humidity on the air dencity. It then displays a reading in metres above sealevel. it basically tells you that the air density at the moment is simmilar to air dencity at a place much higher or lower above sealevel than you actually are.
This gives me an accurate indication if the gun has shifted since I last used it, providing I dotted the Density Altitude down the last time I used the gun, it tells me even before I fire the 1st shot in which direction it moved(up/down). But not by how much. The first sight in pellet tells me that anyway, so its just gadjetry fun I guess.
What it well tells me is that if I detect a shift and I see a change on the DA reading, I know its inviromentally related and not my gun messing about or acting up.
I've noticed a 1milldot shift with every 200m or so DA increase or decrease.
Use it dont use it, just fun messing around with the gadjets.
I've just done some digging on that. Looks to be a useful tool for exactly what you're describing... if you can correlate a shift with a change in density altitude, like you say, you can get an inkling as to whether it's the gun or scope or the environment.
I've been struggling for a while to look for a model of measuring air density, which can change between hot, cold, dry and wet, and hot & dry can be denser than colder and wet depending on air pressure and humidity or vice versa.
Think I might have to look into this as a long term project. It will be interesting to see the changes in the UK as opposed to other areas in the world. Like you say, we don't often get the dramatic changes you do over there.