You'll start as 11B, which is infantry. And you'll then volunteer to airborne school and if you're accepted you'll then volunteer for Ranger school and if you're accepted, you'll find that everyone there wants to do the same so you'll have to be the best of the best of the best of the best.
But it's definitely possible.
And then you'll get assigned to the shooting team and never get to do anything.
Regardless of where you're assigned, all Army snipers are Ranger trained. So the only path is through 11B.
Don't worry about "technique" for shooting--you don't qualify at ranges beyond the "point and shoot" range. Besides which, the M-16 and its derivatives are possibly the least accurate infantry rifles which have ever been adopted by any military at any time. The point behind infantry battle isn't accuracy, but volume of fire. The guy who waits for the shot will be overrun.