I need to find all collectibles on two maps in coop mode

What's the purpose of semi auto rifles if bolt action ones have so much more damage? Yes they have high fire rate, but is it viable to spray and pray at long range?

Searching for a mate.

-Does enemy every stop searching for you once they get suspicious, seems like they never stop ? -Is there a finite amout of enemys on each map, so i could basically just kill em all ? -Bushes don't break line of sight if you are not inside them ? thx in advance...

Help me