old news. Us nra has an official smallbore target for 200 yard prone shooting, dimensions are under rule 4.13:
In the 1990s, i found 200 yard practice w/ a .22 rifle was good training for long range prone. (have not shot 200 yard smallbore in over 10 years, should probably restart doing it, as recent long range shooting performance is slipping badly.)
note: Do not use cheap .22 ammo. From experience from the mid- to late 1990s, federal target ammo is the lowest end ammo type to use. Use anything less, and elevation spread is a serious score killer. More expensive ammo (i.e., federal 900b, 1000b, or eley tenex) holds slightly better elevation, but groups are rounder. (yeah, great compromise - save $20 in centerfire ammo costs by shooting $10/box rimfire ammo.)
200 yard smallbore shooting is not a popular competitive event in the us, mostly because of equipment limitations. Many scoped rifle shooters found they needed to hold off to hit the target, since their scope mounts ran out of elevation before reaching the setting for 200 yards. Iron sights are limited by elevation as well, though use of an adjustable front sight base helps considerably in this matter.
For more info on us nra smallbore shooting, an online copy of the rules is available at
https://competitions.nra.org/media/7745/nra-smallbore-rifle-rules.pdf
hope this helps.