I'm not too big on shoulder presses with a bar. To the front feels funny, and behind the neck feels funny. Ideally I wish I could bring a bar down right through the middle of my skull, but I can't unfortunately. So I use db's or sometimes machine presses.
I did 315 a few weeks ago. Freeweight, seated. Got to 3 reps before racking it. I probably could have hit another 2 reps. But your shoulder girdle is not designed to handle that kind of weight.