Nice job of work!
You probably used the best glue for the task, IMO. I would've probably used epoxy, but who knows which is better. The main concern with any glue would be the disparity of materials and how they react with each other and the glue when subjected to extremes of temperature. (Since the gun probably won't see a snowy cold day in the woods ever again, it's likely a moot point.) May well be why the original plate fell out.
This one is a .22 Hornet, I hope that the only thing it sees is a sunny June afternoon taking care of the local woodchuck population.
John
