Ok knowing something about sniper rifles I got to say the Space Marines sniper rifles are sub-par. 200m range? really? In the Civil war confederates where killing union soldiers at 800m with whitworth rifles. My m4 can shoot 500m. And no armor pen?! HA, google sniper rifles and take a look at some 50 cal rounds. So lets fix this shall we.
Astartes Sniper Rifle Class: Basic Range 1200m w/scope ROF: S (sure there are some nice semi auto sniper rifles out there in present day for example the dragunovs, but I can see limiting it to Single fire and allowing rapid reloaders to maybe increase it to 2 rounds) DMG: 3d10 + 5 I (what it does more damage then the pistol? if someone asks that I am just going to laugh) Pen: 8 Rld: 1 full Special: Accurate, Felling (1), Reliable. Wt 5 Req 20.
There add that to your games and you might have people actually want the sniper rifle. That needle weapon in the book sounds like something an Eldar would use or something.