Given that the 1st Gen short actions have a 4.5 screw spacing and were called intermediate actions I was wondering what the max cartridge length would function in the magazine. I have 2 pre-1966 long actions and one has a 7x57 barrel. It looks like I have about .5 inches of extra room when loading .284 139gr SSTs. You can probably guess where I am going. Could a 7X57 work in a 1st Gen short action. The extra room in the long action bugs me even though it feeds all rounds perfectly. If it would fit, a 1st Gen short with a 22 inch 7x57 sporter weight barrel could make a really light woods rifle using lighter weight bullets.