I want an 870 to play with. I'd like to start with a basic shotgun with a barrel with screw chokes. This way I can return it to original condition from any modifications. The tricky part seems to be the extended magazine. There are mag extensions for 870's but I read that a stop prevents the shells from going beyond the original magazine. If I choose the 870 tac with the integrated extended mag, will the bird barrels still fit?