Thanks for the info! I've found em new all over but hopin for a cheaper used one as I have no real need in a .22 but for plinkingHere you go.
https://www.primaryarms.com/cmmg-22lr-ar15-conversion-kit-bravo-3-25-round-magazines
But seriously...your Henry is worth more in real life than a .22 upper. I know it costs less, but IMHO, it's worth more.