No sniper rifles, or make them 500 perk points.
They are massively overused in FPS from what I have seen, and turn 'gameplay' into 'I'll hide at the crest of this hill and rack up easy kills while my team dies to the man down below'.
In general, I'd go exponential on perk costs for infantry weapons based on rarity, and start at 100 perk points or so as a test.
For (a rough, off the top of my head, no play balance testing)example:
German infantryman:
Kar 98K: free.
MP 40: 10 perk points (usually 1/10 men in your average German infantry squad).
Binoculars: 10 perk points.
leMG 34, leMG 42: 50 perk points (yes, 1-2 per squad, but you don't want firefights with 50% of the weapons being used being LMGs, no?).
G 43 (German semi-auto rifle, fairly rare): 100 perk points.
StG 44 (German assault rifle, more common that G 43 but didn't appear in 'general use' - i.e., with non-SS/FJ units - until late 1944): 100 perk points.
Add a scope to Kar 98K or G 43: 500 perk points.
Mike/wulfie