Shooting Steel

[jacpor]

You have to be sure also that the chokes are made for steel. Some chokes are for lead only (some sporting clays chokes will handle lead only).

 

[scruffee]

Yeah you definitely used the wrong choke tubes for the job. The chokes are rated for steel or lead, too bad you learnt the hard way.

 

[silver 55]

J B Weld makes a thread replacement compound.
If that was my shotgun, I would clean up the threads as best I could, and try to thread the chokes in. Use a choke that has good threads. If this works, clean up the barrel with ether, mix up a bit of compound. Smear some of the compound on the barrel, put release agent on the choke and thread it in. When you unscrew the choke, if it looks like the threads are good,safely test fire it.
If that doesn't work then I would go on to one of the other ideas.