I do not see bulging a barrel with a rod , lead is still softer then steel , with a slug stuck and then another round fired I can see bulging , and btw I had a rifle 264 win mag a ex brother in law shot a 308 win. fmj out of and stuck the slug , I gave the rifle years later to a guy and he drove the bullet out still has it in his gun shop and he said the rifle would still drive tacks .