a 5/16" dowel rod (brass, if you can afford it, hardwood if you can't) about 3 or 4" longer than the barrel. Slide it down to the obstruction from the muzzle end and hammer the obstruction out. A good deadblow hammer would probably be best for this, but a heavy plastic tipped hammer should work, as well. A regular carpenter's hammer or ball-pein will damage the end of your dowel much more quickly than one of the softer ones, but if that's all you have, go for it.
It's doubtful that the stuck patch/jag has damaged your bore.
Depending on your rifle, a 5/16 might be slightly too large to slip down the bore. Try it.. if you have to force it, go with a 1/4" dowel instead. You want to use the largest possible dowel, that will still slide down the bore without having to be forced.