Help with Shotgun barrel

[Elementbilly]

I recently aquired a Winchester diamond grade skeet shotgun. I was guessing its 410 looking down the barrel but noticed the barrel says 12 gauge. Is there a way to remove this insert? I can take the end out but the rest wont budge by pressure alone.

 

[Elementbilly]

Ended up figuring it out. Just took more force then expected.

 

[mike4sigs]

glad you figured it out,
now tell us about it please

 

[AmmoManAaron]

Looks like it had a set of .410 subcaliber tubes installed.