I'm sure this wont work, the spx has a barrel extension and also 4 lug rotation bolt unlike the bulldog. ( I have both ). My guess is the Asil wont have a direct compatible barrel that isn't made for Winchesters orders. It's worth checking though.
Sounds like you're exactly the guy the OP needs. Would you be willing to remove the barrel on both shotguns and compare?
I did. They're completely different designs



























