Yep, you sure can and you can even use 38 Super brass to shoot in your 9mm Largo but DO NOT load it to anything higher than 9mm Largo pressures. I bought one of those surplus Star B's a long time ago and got the calipers out and started measuring. The 38 Super brass fed well and shot fine but be mindful of the loads you use, since the guns chambered in the Largo aren't as strong as the 1911.