I think at 30% acc. you would do well,if not,...
maybe ur not using the map?
Like when you shoot, always try to be near an object a wall or pillar to bob around while trying to frag your opponents.,
Use the map to protect your self from getting damage.
So you must learn the maps,and know where to scrim and where not to.
This applies to FFA.
I been playing for 11 hours now and I only have 19% acc with rail.
Maps I know i do well,maps I don't know,I do not so well.
So practice and get to know your maps and you will develop your skills.