Ya, own a 430 in 20 ga.
So from what I gather if I had a 12 ga the 20 ga barrels are going to have even a bigger gap than the 16 that you own.
It's kind of a win/lose situation. They will fit but they have a gap on the inside of the frame.
I'll measure up the 20 ga in a bit, just having my morning cup of joe.
