If you used the 16ga 2 3/4" shells you be pretty close with the 20ga 2 1/2" shell.
Shame you sold the 16ga but I can understand that been offered good price for mine. I also have 20ga model 12 and at time I wish it had 3" chamber so if your only shooting few boxes a year I get the 20ga 3" chamber if they have that.
If your hunting over dogs 410 or 28ga be a good choice.
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