Originally Posted by P5Ret
I think you may have an issue. My understanding is you can replace mag springs, but not the body of the mag. In the strictest sense of things you have built a new mag.
That's just an example of how useless the law is.
Suppose your cousin Cletus drops an axe on one of your 30-round AR mags, puncturing the body and preventing the follower from rising more than half way.
Certainly, you can pull the baseplate, spring and follower off the damaged body, and install those in a new body.
Later on, the baseplate drops off and the spring escapes with it into the snow; certainly you can replace those pieces, leaving just the follower from the original mag.
Later, you get a bad reload that does a case rupture down through the mag - follower gets trashed. You can replace the follower.
Now there are no original parts. All legal.
And yet, it appears to be wrong to run over an existing legal mag, completely destroying it, and then assemble a kit into a complete mag.
Such clarity of thought went into the law!