Actually, a lot of people know the rules as they’re written in NYS law books. While there is some grey area in the laws, “high capacity” ammunition feeding devices are pretty much in plain English. Unless the magazine was produced before Sept. 94, they can not hold more than 10 rounds of ammunition (for regular civilians). That’s why you usually see pre-ban mags going for $20-30 easily while in other states (such as VT and 44 other states) they’d go for much less because they have no laws concerning magazine capacities.