And I'll agree with bruben7886 as well. Letting a professional handle it is your safest bet - especially since it sounds like it's not just tissue paper in there anymore. Also, one other thing...rust expands when it gets saturated with any oil, but PB Blaster (an incredible solvent I always have on hand) will actually break down the rust into a liquid and shrink it rather than expand it.
You may be dealing with the tiny coating of rust in the barrel actually having expanded and "cemented" the tissue paper in place. The PB Blaster will flush out the cutting oil you've used, replace it with the solvent, and could likely free the whole mess.
PB Blaster 11 oz. Penetrating Catalyst Lubricant 16PB-THD at The Home Depot. It works by both breaking down the chemical composition of rust into smaller molecular compounds, and the oil becomes the suspension which wicks away those molecules thereby freeing up space between the rusted parts. It is one of the best possible rust removers out there while being safe for most applications. The longer it's left to do it's work, the better. 24 hours or more is best.
There are alternatives which have been tested to work better under laboratory conditions, but I am not sure what timeframes each were given to do their work. They say that Liquid Wrench, out-performed PB Blaster but in my experience I have found that PB works nearly 100% of the time, where penetrating oil only works maybe 30%.
The one combination or "home brew" that apparently works the best is Acetone and Automatic Transmission Fluid (ATF). The Acetone is a very strong solvent but comes with significant risks. It is flamable, noxious, and will melt paint, plastic, and other finishes on contact. It also sucks the oil out of your skin leaving a dead white layer. Contact with Acetone too long will cause cracking and bleeding of the skin.
The ATF has "detergents" built in which are designed to keep the metal surfaces of the interior of the transmission from building up any residue and also to prevent any corrosion. Whether these detergents are safe for a gun barrel is completely unknown to me. If it were my gun, I'd go with the tried and tested PB Blaster. See below.
For all of you that are mechanically inclined and dealing with frozen fasteners:
Penetrating Oils Compared
Machinist's Workshop magazine actually tested penetrants for break
out torque on rusted nuts. Significant results! They arranged a subjective
test of all the popular penetrants with the control being the torque
required to remove the nut from a "scientifically rusted" environment.
Penetrating oil .......... Average load
None ..................... 516 pounds
WD-40 .................... 238 pounds
PB Blaster ............... 214 pounds
Liquid Wrench ............ 127 pounds
Kano Kroil ............... 106 pounds
ATF-Acetone mix............ 53 pounds
The Automatic Transmission fluid (ATF)-Acetone mix was a "home brew" mix of 50 - 50 automatic
transmission fluid and acetone.
Note the "home brew" was better than any commercial product in this
one particular test. A local machinist group mixed up a batch and all now
use it with equally good results. Note also that "Liquid Wrench" is about as
good as "Kroil" for about 20% of the price.