I know you have new mags, but while you're waiting for your other new stuff to come and if you have a good caliper, measure the distance between the nibs and the very top of your mags. It should be at least 1.5 inches. Take a look at post #22 on the last page of this older thread. - Bob
https://www.milsurps.com/showthread.php?t=73505&page=3
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