Hey long range folk,

when a scope for sale on a site allows setting the calibre (which makes sense and doesn't change on a gun) but also the grain, does that only apply to the way they are pre sighting it or something?
Realistically I may want to try running different weight rounds through my rifle, will I need to make adjustments going up or down even 5 grain? Is the scope designed to only handle ranging for one grain weight?

I understand the drop won't be significant until 2-300+ yards so this may be moot for any target shooting I ever do. The rounds I am specifically looking at are 50/55gr .22 - 250 REM

thank you for any clarification you can bring me.