Yep. I didn't want to possibly ruin a mag in a vice, so the first time I built one, I used a scrap piece of 2x4 and a band saw to make a receiver block from wood and painted it black. I bought an actual receiver block shortly after that, but the wood one worked just fine. I even chiseled a mag catch relief in it...lolI found if you don't have a vise block you can use a metal mag and wrap it in some electrical tape for a snug fit if it is loose