I've never needed to remove a hinge pin, but from what has been posted here, those that have removed it, used a press, if yours came out that easy, I would be suspect of that. I would probably remove it and try to put it back in but rotate it one spline at a time until the barrel locks up good again, it will take a lot tries unless you get lucky. Too bad you didnt index it when you removed it, then it would have been a simple matter of aligning the marks.
If there's any wear marks on the pin, that should give you an idea where it was originally.
The other alternative would be to just send it back to H&R, give em a call first on their toll free line (866)776-9292, explain exactly whatcha did, and go from there.
Good luck,
Tim