Was it Bear or Wolf?
I have had experiences similar to yours with steelcased ammo of that sort (In H&K 40 & 45) I believe the case may have split and hung up.
Put the safety on (down)
Drop the mag (unload the pistol)
If as you say whats' in the chamber is an EMPTY FIRED case
(I assume a failure to extract)...
I solved my problem by putting a wooden dowel down the barrel and whacking the dowel with a hammer till the slide moved and the case fell out; and not using that ammo again...Case expanded and split hanging everything up; I doubt it damaged the pistol, but I'd have it checked over if it feels the least bit stiff or cranky; Smiths' are pretty hard to break.
Obviously if theres' a live round in there, don't do this (not saying you're stupid, but I've seen this tried too)
Cheers, TF