I'm about level 7 now and haven't found any sniper rifles, where can I find a sniper rifle?

Create your own out of the guns you have! That's the easiest way.

I built a sniper rifle with parts (pipe sniper at level 6). I bet the good snipers will come later on.

I found one in a house in Concord. A .308 pipe sniper rifle. I was level 5.

You can hobble together a sniper with the new crafting system from almost anything.

That said, I'm level 11 and just found a Short Barrel Hunting Rifle (My favorite gun from recent Fallout's.) Legit sniper rifle, here I come.

According to the official guide, there's no actual basic Sniper Rifle like there are in previous games. However, you can make a passable one out of a Pipe Bolt Action Rifle for the early game. As for an actual Sniper Rifle, the Hunting Rifle can apparently be converted into a .50 caliber Sniper Rifle with the proper mods.

I posted that then went to play more an immediately found 2 sniper rifles. They are large high power .308 bolt action rifles, like an M500, but literally called "Sniper rifle". Stronger than the "Bolt rifle".

Seems like they start popping up around level 10, or at least a bit away from the starting area.

Kill Preston Garvey and take his.

I made an early one from a pipe rifle and my current one at level 13 (with Gun Nut 2) from a Hunting Rifle with the Marksman's Stock, Medium Scope, Long Barrel and a new receiver to boost the damage. It didn't take much at all, really.

When I get Gun Nut rank 3 I'll be upgrading to a .50 cal receiver and sticking a suppressor on it. Beast mode.