Just received my Hawk Optics DVD in the post today.
In case you haven't heard about it (been living under a rock, back of a cave, or went on the last NASA lunar econo-buck cruise...), its about the new scope from them with the Nick Jenkinson (sp?) designed reticle in their SR6 and SR12 models.
Quite informative indeed, gives a new insight (well for me) about rangefinding.
In fact I would reccomend this DVD as a newbie tool about airgun trajectories.
Seeing as it's free - well you can't complain.
Runs about 15 - 20 mins IIRC.
Must say that I'm jealous of Nick's range - all nice and green, pretty flowers, bit of a breeze, sloping grounds, bunnies and other wildlife (flies included) bouncing around the bushes.
Check it out on http://www.hawkeoptics.com