Just be careful if you use tape and it gets on the bluing or gun finish… some adhesives will strip bluing, or cause rust quickly. I buy EVA foam that they use for COSPLAY armor and stuff… for pistols, I use the foam “dowels” and cut a V-shaped channel, then use Saran Wrap and wrap the entire gun to prevent the dowel from shifting and to keep moisture away from the gun while I’m forming since I don’t have a bunch of blue guns.