When I first met Tony in the early 1990's he had a 'mini' Model 21 in 22lr. Later he started making them in 28 gauge and 410.
I waited a long time before I had the nerve to purchase one from him but it was well worth the money and wait.
I am not sure if the reciever sizes are different between the 22lr and 28/410 but in any event they are smaller than a 20 gauge Model 21 receiver and make an excellent bird gun as well as a great piece of gunmaking.-Dick