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. Another is the AR-15 Magazine lock from D.D.'s Ranch. (The link to their websites 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.
IMPORTANT NOTE: If you are using a device that disables the magazine release with a screw, do NOT tighten it down enough to squeeze the CompMag. Squeezing the CompMag with the magazine catch will result in rounds not being able to pass through the magazine. Always check functionality of the firearm and the ability for rounds and the follower to move through the magazine BEFORE using the epoxy to seal the screw. The CompMag is not compatible with the Mean Arms MA Lock as it squeezes the CompMag.