Actual velocity will vary , and so to will drop . Ive been shooting 22 sv at 100,200,300 yds for a couple of years . I started using the chronograph, and realized , 28 " barrels are generally slower than a barrel 16-22". So on a couple of tests I cut the 28" down 1" and recrown, retest vel and drop . I did this until I hit 19 " , vel continued to increase until that 20" point. At first,drop from 100 yd zero to 200 yd was 45"
Using Fiocchi Super Match 320 , after trimming to 19" ,drop reduced to 39" . Same box ammo , near ident. Conditions. The powder burn in 22 lr can be as short 14" ( i read it somewhere , so it must be true ) . Sorry for rambling , the point is ,try ammo your gun likes , and chrono it , compare to its published vel. if your close to published vel all is well , if a large diff in vel figures , your drop will increase will barrel lenght ( along with other , chamber,leade,barrel diam , cond ,etc,etc).
One of my 28" barrels will shoot some HV ammo under the speed of sound.