Like Cutter, I also worked from a solid model, no drawings.
The .357 is basically just a scaled up RGG gun, the only real difference being center fire. The gun ends up being quite large and heavy, mine is 34 inches OAL and weighs about 80 lbs. The main housing on mine is 4-3/8 OD. Because of the size of the gun, material costs can get really high, especially if brass is used. The size of the gun one makes may be dictated by what materials are available, not to mention barrels.
Another point worth mentioning is that I would not recommend building a .357 or similar until a person has built a 22 rimfire first. Again, the material costs mean mistakes and remakes can get VERY expensive and then there is the huge difference in power and stress on parts. My .357 went pretty smooth but that was because I did a LOT of learning and mistakes on the 22 first.
