I've taken an intense interest in the new law and I've read it several times. IANAL, but here's my interpretation of how it will affect the M1 Garand.
The M1 Garand is NOT an "assault weapon" because it does not accept a detachable magazine. However, this doesn't mean it's exempt from the NY Safe Act. Let me explain.
The main issue is the definition of "large capacity ammunition feeding device" or LCAFD for short. A LCAFD is defined as follows:
"Large capacity ammunition feeding device" means a magazine, belt, drum, feed strip, or similar device, that (a) has a capacity of, or that can be readily restored or converted to accept, more than ten rounds of ammunition, or (b) contains more than seven rounds of ammunition, or (c) is obtained after the effective date of the chapter of the laws of two thousand thirteen which amended this subdivision and has a capacity of, or that can be readily restored or converted to accept, more than seven rounds of ammunition; provided, however, that such term does not include an attached tubular device designed to accept, and capable of operating only with, .22 caliber rimfire ammunition or a feeding device that is a curio or relic...
A subsequent section says that "Curio or Relic" (which I'll call CoR) LCAFDs may be legally brought into NY but must be registered.
I believe that the internal box magazine
of an M1 Garand is considered an LCAFD since it can hold over 7 rounds, and only rimfire tube mags are exempted.* An original Garand qualifies as CoR because the rifle has been out of production for over 50 years, so it may be lawfully transferred into the state, but the internal box magazine must be registered.
As I read it, the definition of LCAFD clearly includes en bloc clips (and stripper clips for that matter).
8rd Garand clips that qualify as a CoR may theoretically
be brought into NY legally, but proving that the clips are over 50 years old may be tricky. Once (if?) that hurdle is cleared, they still have to be individually(!) registered.
Due to the registration requirement, I foresee many New Yorkers sticking with 5rd clips from this point forward, until someone comes up with a special 7rd clip.
*Yes, this apparently encompasses 10rd Lee-Enfield magazines as well!