Originally Posted by Vestas
I'm surprised that this affects competition HT/HFT airgun shooters though? Sites which have +/- 30 degree and 30 yard+ targets must be few & far between?
We do see them now and then in the UK, it's much more common on the continent. The steeply angled targets tend to be at close range, so less than 15 yards usually. It's very rare that targets are at a distance and angle that means you need to do anything other than remember the Rule of 15's though.
Less than 15 yards (no matter what the angle) OR less than 15 degrees - Just forget that it's an inclined target and aim where you normally would.
More than 15 yards AND more than 15 degrees - aim inside bottom of kill.
And that's it - no calculations, not cosines, no inclinometers... just remember 15, and get on with your day. That was probably one of the the first answers given in this thread, but it's still gone on a good while. Welcome to Shooting The Breeze. Ask a simple question and you're guaranteed to get a very detailed answer whether you want it or not.