Re: Explanation of mrad?
An mrad is a milliradian, which is 1/1000 of a radian. At X distance, one radian equals an arc of X. So an mrad at X distance "covers" a space of X/1000.
Example: at 100 metres one mrad equals 0.1 metres.
Most scopes have clicks in 0.1 mrad or 1/10000 radian. Which at 100 metres would be one centimeter.
But you really should never think in terms of "clicks," but rather angular measurements. So, if my bullet impacts four centimetres low at 100 metres:
I should NOT think: I need to bring it up 4 clicks.
I SHOULD think: I need to bring it up 0.4 mrads.
And then simply turn the turret/dial to increase by 0.4 mrads. Never listen and count clicks, as this will cause error, be slow, and is just plain dumb.