Strelok is good, they have a free and a paid version. Also many are using 'Shooter' which works well and has the 'Litz' validated BC info for various long range projectiles, small cost of about $10 from memory.
I use Shooter these days, but have tested it side by side with Strelok and there was nothing in it, it will just come down to the different 'look and feel' of the apps, as to what you prefer.
Bookmarks