Evil Bots and Stuff

I have a 12 gauge shot gun with a barrel threaded for choke tubes. Can I shoot a slug through it. In Illinois, you are not allowed to use a high powered rifle that I used to to use in other states. Will it jam or harm the gun??

20 gauge 2 barrels scope

I have a 12 gauge shot gun with a barrel threaded for choke tubes. Can I shoot a slug through it. In Illinois, you are not allowed to use a high powered rifle that I used to to use in other states. Will it jam or harm the gun??