Reloads or fresh factory ammunition? If it is factory, and the dowel test shows a squib or case separation, document it with pictures and ammo case lots, etc. Speak with the company who produced the rounds to determine best course of action...not the best and fastest resolution in most people's minds, but a squib round can cause extensive damage even if it is only a single round. It's smart to let the manufacturer deal with the costs associated.
If it's reloads, do the same and get in contact with the producer...determine from there.
If they are personal handloads: do the dowel test, and if its a squib round, the gun is likely safe to knock the round back out through the chamber while securing the frame in a vise. Don't use a metal rod if you can help it, and if you do wrap the end in a piece of cloth or leather to protect breech face if the rod penetrates the brass/prier pocket)
If this is the case, mic (measure O.D. of) the barrel to determine outside dimensions do not include a ring or bulge. IF they do: find a new barrel/gunsmith. If they don't, check with a good quality bore scope to determine the viability of the barrel for future usage.
If the round is a FTF, then you should be exercising caution on trying to remove the round, and should meet with a qualified gunsmith at a facility able to handle FTF live rounds (most ranges with gunsmiths can do this).
If you must, you can take a piece of hardwood block and tap backwards on the top of the breech face as mentioned by another poster above, and perhaps get the weapon to open up. But exercise safety and caution, and don't stand in front of or above the path of the bullet.
When you do get it open, check for gouging, twisting, warping and damage to all parts of the barrel lock up system, including lugs, links, bushings and other areas (this is a general statement, not necessarily specific to this weapon), before attempting to reassemble/fire.
www.netgunsmith.com is going to be putting out some great tutorials on gunsmithing (far more comprehensive than this in the next several weeks, I invite you to take a look if you would like.