My primary question for those doing it is "What will it feed?"
If I were to do this, my main attraction would be to an aggressive flat point in the 150-ish grain range like the NOE/Ranch Dog. Given that it's a gun designed for com-bloc 123 grain spitzers, how well do bullets like that get out of the 10-rd mag & into the chamber?
If that's a go, what do you fuel it with? In a bolt gun, the obvious choices would run toward the slow pistol powders, but what makes the overgassed gas gun tick?