Not to mention that the rifle should be locked to semi only since a full auto burst from a hot rifle is not cool even if you're at the Minimum Engagement Distance.
Starting with a TM VSR is always a good start but the other one is the M700 (I believe it's the Tanaka M700 you want).
If you're in Philly TheWarStore in NY isn't that far. Looks like all their spring sniper rifles are out of stock but I'm sure it's just they're items that don't move fast and are special order:
http://www.thewarstore.org/airsoft/s...airsoft-rifles. They CA they have seems like a pretty good bet, get nothing else.
Otherwise the SystemA PTW might be a pretty good "sniper rifle" if you could lock it to semi (I guess via MOSFET) and put in a Red or Gold Cylinder (500 and 430 FPS respectively? They correspond to an M150 and M130 IIRC).
PS: No doubt that HPA is more consistent than greengas. That's actually the reasoning being Classic Airsoft being better than GBBR's (not only that but they also use regular AEG mags, no cooldown, and such).