Turk--I have 4 of the Belgian Auto-5's and also the new A-5 Sweet 16. The two 20 gauges are Cylinder and IC choked, respectively. Both of those have vent ribs. They are wonderful grouse, quail and rabbit guns, and I've shot pheasants with the IC choked 20 gauge.. The two Sweet 16's are 1): a modified choked, round knob, blond wood model with vent rib which has killed a number of ducks and roosters, and 2): a Sweet 16 with vent rib and IC choke. Three of these 4 are in 96-99% original condition. I would never trade or sell them. The Belgian models, particularly in the vent-rib open-choked 16 and 20 gauges, are becoming quite collectible if in good original condition.
The Sweet 16 A5 I bought late in 2018 and it is a marvelously light and responsive bird gun you can walk all day with! This season, in Illinois, Iowa and Indiana I've shot about 2 dozen roosters and at least that many ducks with it. It fits me like the proverbial glove, and recoil is negligible.... I cannot recommend these guns highly enough--but don't shoot steel in the Belgian-made guns.