Just a thought, but have you considered building a 20-222 instead? They feed smooth as butter, necked down Lapua 222 brass lasts forever and is top notch stuff. The 20-222 is only slightly larger in case capacity than the 20-221 or 20VT so you only burn about two more grains of powder and barrels last just as long. When I had my 20-222 built a few months ago it originally was going to be a 20-221 build, even bought the brass and dies, but I knew I wanted it to reliably feed from a conventional hinged floor plate or HS Prec detachable mag box and it seemed like the 20-221 or 20VT was hit or miss on smooth feeding so I started looking at the 20-222 and once I did, I never looked back. I ended up having a HS Prec detach mag system installed and my 20-222 feeds smooth as silk. just something to consider.