i sucked at no scope,but now i got like dragonuv,m21,50 cal,stuff like that,i just used the 50 cal and run around ownin R1(ps3),i just aim like i am usin a reular gun,without a scope or red dot,i just seem em,keep taret on them,and then press the shoot button about 4 times then there dead,u must do quick they might get you first,when u get good its fun
using bolt action rifles,most games its a requirement,I just see them,maybe get close if they dont see me,then shoot and shoot and shoot until they die,i dont really G shot or anythin,i use like a reg gun,just slower
idk if this helps any,but i hope it does