The only definition that counts is the one that is accepted in a court of law.
That definition will be set when expert witnesses from both sides each give their expert opininions under oath in a proceeding requiring the answer to be sought. Sadly this will probably take place when someone is charged, and their defense rests on the definition.
When that time comes, the "expert" for the state will need to come up and testify that a dog has 5 legs because they state has decided that a tail is a leg, and the defense expert(s) will have reams of technical manuals, army publications, and an entire suite of history on their side to show that a clip is not a removable magazine, and that a M1 Garand is not an assault rifle.
All of this is based on the presumption that "some" LEO will be stupid enough to arrest someone for shooting one, and "some" prosecutor is stupid enough to try to make a case that an enbloc clip is a removable magazine. The decision will be made by a jury of 12 citizens. I have sufficient faith in the system that they will not ALL believe after it's explained to them in simple language that a dog does not have 5 legs just because the state says so. If it were me, I'd hire someone who was retired from the Army Research and Development Command at Aberdeen MD as my expert witness, but that's just me.
A "Feed Strip" feeds a few obsolete machine guns. It has a formally accepted techncal definition as well. A Garand enbloc clip is not a "feed strip". See Japanese Type 92 as an example.
There's enough really bad stuff in this bill to concentrate on, the Garand issue is just chicken-little stuff. Move on.