Barrel disaster question

[Tom]

Hi
I'm looking at a gun that I'm guessing someone wanted to open up the choke on. It appears they drove an oversized mandrel down the first inch and a half of the barrel, it swelled the end of the barrel getting rid of the choke. To make matters worse it appears to have been a hexagon mandrel so it's not only swollen but has the lines pushing out even further. I feel that just trying to hammer the metal back would be sloppy I'm pretty sure it must be stretched and not sure of the result.

I like the gun and it is a high grade, short of chopping the barrels I'm not sure how I would handle this. I do not have any pictures, I am only looking at it I won't buy it unless I can come up with a good plan to restore it.

Any suggestions greatly appreciated.
Thank you, Tom