boscoebrea,
Thanks and yes, in real world conditions, the (sorted by diameter) .217 KO slugs are the most CONSISTENTLY accurate ammo using an FX Crown MK1 in a chassis with a 700mm Superior Heavy liner at 100 yards out of all the pellets and slugs I have tried thru the Crown MK1 in .22 cal. However, I haven't tried EVERY possible combination of liners, speeds, and pellets/slugs. I have had several combos which showed good 100 yard accuracy, for a time, or only with a clean barrel, or only in certain conditions which haven't stood the test of time/different conditions enough to be called CONSISTENTLY accurate at 100 yards. For example, I can shoot tighter 100 yard groups with JSB 18g out of the 700mm Superior liner, but ONLY in calm conditions. As soon as the wind blows at all, the groups open up.
Posting these targets is only to provide a GUIDE and show what is POSSIBLY something that others could replicate or improve on.
For MY Crown MK1 in a chassis, this is the most consistently accurate ammo/liner/speed combination that I have tested, but sooo much is dependent on sorting the KOs by diameter(I can't shoot striaght out of the tin). I haven't FULLY explored the potential of the 700mm Superior liner(having just received it a couple weeks ago), but no combinations of pellets/slugs at different speeds have beaten the KOs with 700mm Superior Heavy. I believe that the Crown MK2(with more power) PROBABLY has the potential for better 100 yard accuracy.
As far as how it is done, just start shooting test targets at whatever distance is important to you. Make changes, 1 at a time(different speed or ammo), and see if accuracy improves. When accuracy impresses you, keep things the same and shoot in different conditions and days/weeks at a time, to see if anything changes. Make detailed notes of what combinations that you have tried and in what conditions(temp, humidity, wind, etc...).
Good luck
