Yes, technically by the law it IS legal but if you get an LEO with a bunch up their ass they could give you grief. I’ve been stopped before and had officers look through the rifles to make sure there were no rounds physically in the chambers or internal mags and have looked over the the loaded ones elsewhere and have never had a problem. 99% of the time though I still don’t carry loaded detachable mags in the car for the AR’s and stuff.
The main problem is that the laws have not been updated at all to accommodate new products and standards… It’s the same bullshit with buying pistol ammunition for rifles. The law was written back before the advent of most of those firearms and it wasn’t legal to purchase the ammo w/o a fitting permit, and just hasn’t been updated to current standards in NY. It’s why just about any gun store will still sell you the ammo(because they know thins) and most other chain retailers(IE wallmart) tend to give you shit about it.
Sucks, no if ands or butts about it.