One can easily put a 16 gauge load of powder and shot into a 20 gauge. However, if you plan to make your own stock, buy the barrel elsewhere like TOW and get a 16. I built the Chambers 20 gauge and it shoots great. I think the long barrel is the reason, or at least part of it. I think Chambers can make a precarve from your wood, but you may have to wait a while. (Their precarves are nice.)