I think it would be better if you were to let friend B the use of your own gun and you use friend A's gun. Remember if friend B were to damage friend A's gun, you might not have a friend A for long.
I note that you intend to supervise your friends shooing, but if you are also shooting you can't be on top of his supervision full time.
You would do well to remember also, that if other people are shooting, they might not be too happy if your friend does not have insurance cover.
The best solution is to let your friend use your gun and you just supervise :toast:him.
As the law