There are no guarantees that the standard contours given below are suitable or safe for the calibre or cartridge you have in mind. We usually use our experience and raise the question if a chosen barrel contour looks like it it a little too thin for your application, but that cannot be relied upon. Ultimately, if you choose a given contour - particularly if you change the dimensions and/or add flutes - the responsibility for the safety of that contour in your application is down to you. If you are in doubt, ask.