Yep, not recommended to insert a 28 ga shell in that S&W 1000 , it would fit by golly, and that is where folks get seriously injured, maimed or dead.
Neat gun - shot great, it was NOT a Winchester SX1, and the stamped out 1100 by Rem took the market by storm. Folks bought those instead the Machined SX1 . Well some of us folks stayed with the old school and machined parts and craftsmanship guns for quite a bit longer...*grin*
I always wished the SX1 had been made in 20 and 28 ga...would have been a great classic then - and now.