I'm in NH as well, but I can buy syringes with blunt needles in various gauges at the local hardware store. They are in the plastics fabrication section. The needles are not sharp, just metal tubes cut square. I think it would hurt quite a bit to inject yourself with them, so they are legal. Maybe NY state allows them too.
The needles came with a 18 or 20 gauge needle on them. But for safety sake i'd go with the hardware store variety.