No one can wave a wand and say that they are all safe, whether the old gun has proof marks or not. The gun is really not that smart and it is working under an amount of pressure that they were designed for. I do shoot ALLOT of Damascus. I try to stay at a PSI of no greater than 7000 psi. But, I cannot or will not tell you it is OK for you and your guns. All of us who try to control an explosion in our hands in front of our faces, all have to be willing to accept some kind of risk. Stay below the pressures your guns were designed for and that the barrels are sound, you shouldn't have a problem. I shoot Bakers, and all the ones I had were designed to shoot either Nitro or BP, again, depending on pressures.
