Leo Harrison

Hey guys So I'm pretty new to DayZ standalone, only played about 40 hours, however I've got to grips with it pretty well, you know, I can get myself from town to town, knowing my whereabouts and squiring decent loot. For the time I have been playing I have been searching and searching for specifically a mosin, and of course attachments, however just can NEVER find one! Am I looking in the wrong places? Are they actually quite rare? I am confused because when I talk to players they say AK's are rare, but I find LOADS of them, and I do mean loads. So can somebody maybe tell me, where can you find them? Which buildings/cities e.t.c... Also, are M4's only spawned at heli crash sites? Thanks, Leo