Well I haven't gotten to use it, so I can't speak to its accuracy. The M24 then?
What M24?
To the accuracy, the M21 has 4, the R700 2 (I just cut out the unnecessacy zeros). With 4 you can still hit on... 200m and a bit above without problems. With 2 up to 500 and more. Laying down subtracts 2. That means the highest you can get with the M21 is 2, the highest with the R700 is theoretically 0. But I set a limit, 0.5. That is still pretty accurate up to 1 km if not farther. So in terms of sniper rifles, the M21 is pretty inaccurate.
And people seriously complain about the sniper rifles not being accurate enough. Theoretically you could hit something with the size of a 3x cube (without missing due to my accuracy limit I think) at a distance up to
1600 meters with my Truvelo. But the scope dots only go until 1000, just as the draw distance limit.
It's the same with the bullet drop. People complain it is
waaay too much!. They complain about some degrees they have to aim up.