The aged look is the easy part. I use formula C26 out of Angier's book minus the Mercuric Chloride. Rusts fine without it and that is some deadly poison. The solution needs to be put on as even as possible then after rusting carded well. You do not want to leave any scale behind to build up. Once you have a nice even brown the pattern is brought out with a Ferric Chloride rinse. I buy a 29% commercial solution and reduce it 9:1 leaving the solution on the barrels for about 15 seconds. My experience is it is better to under etch than over etch. Careful carding produces the pattern. Too much carding and you loose it. To create the aged look a reduced C26 formula of 1/32 strength was applied and then carded. The barrels must be neutralized in a solution of H2O and Sodium Bicarbonate.