We have received many inquiries as to the AR-15 CompMag being used in New York so I thought I would address this topic. First of all, I am not a firearms attorney and we have not had a N.Y. firearms attorney evaluate this product, so this should not be taken as legal advice, but this is how I see it.
The AR-15 CompMag was designed to be a fixed magazine in accordance with California law. California law states that to have a fixed magazine you must break the action of the firearm to remove the magazine. This is solved for California by screwing the magazine in from inside of the firearm.
New York law is different, in that it states that you cannot have the "capacity to accept a detachable magazine". Therefore just screwing it from the inside is not enough to comply with N.Y. law because the capacity is still there.
I believe that there are ways that you crafty New Yorkers have come up with to “permanently attach” the magazine into your firearm to meet this criteria. One solution I have run across is the "Safe Mod" by All Star Tactical. This inexpensive device disables your mag release. (The link to their website can be found below).
Once "permanently attached" according to N.Y. law, the CompMag is an ideal loading and unloading solution for your AR-15.
If you are unsure if your particular firearm is compliant or not, I would check with your local N.Y. gun store or firearms attorney as to what needs to be done for your specific compliance. I hope this helps, Thank you.