A 17 year old should do a time of apprenticeship with the following qualitfications before he is allowed the honour of owning a sacred double rifle.

1 Be capable of shooting a squirrel with a sling shot. He should be able to hit a bottle cap at 15 yards 9 / 10. That is the best practice for using both eyes. (I had shot 10 squirrels with a hand made tree-fork & cycle rubber sling shot by the time I was 15)
2 Be capable of shooting a squirrel in the head with an open sighted air gun at 25 yards. (I had shot over a 100 squirrels with an air gun before I was 17. I even got a few on the run at 15 to 20 yards).
3 He should be able to walk 20 miles in thick bush on a hot day with just a water bottle. Crossing ravines, thorn bush covered gullies & red ant infested forests. He should be checked by a doctor (NOT his dad!) & certified as having skinned his knees, ripped his skin with thorns, cracked his lips from the dry heat, have red eyes from grating eye balls with dust in them & at the end of the 20 mile hunt, come home empty handed. He should then be able to do his home work! (Yes I did that before I was 17 - except the home work bit!)

Ok, Ok - I am just a jellous 51 year old!

On a serious note, Ripp's suggestion of practicing with a 20 gauge shotgun & slugs sounds perfect. The old BRI sabot slugs should be ideal. I don't know why I never thought of it! I have an old Webley & Scott 12 bore that has been mucked with by previous owners - forcing cones & chokes opened out & rib resoldered. That should be a candidate for some good practice before I buy my first DR. I would appreciate any suggestions on the relevance of such practice.