Have you rechambered a Marlin 336, 30-30 to a 307

[RugerNo3]

There is a gentleman that posts as Slim Iorg over at Beartooth Bullets dot com that has done and is currently doing extensive tests with pressure controls on the 30-30. He also has a 307 Big Bore that he has run tests on. His findings are that the 307 is erratic on pressures. The 356 win follows some normally accepted patterns in load development, but not so with the 307. Remember, for whatever reason Marlin didn't produce this chambering for retail. His tests are run using the case expansion guidelines of miking the pressure ring at the web and running all loads to within .0001" constants. It is interesting to note that the 30-30wcf runs higher velocities from a 26in barrel then the 30-30 AI version runs from a 20 inch carbine loaded to the same pressures. His feelings are the 307 in a Marlin is on the ragged edge of the built in safety factor of that levergun design. Headspace will start increasing at a faster rate then is desirable.
I would suggest that you visit Beartooth and run some search on his posts. On one post he alluded to a 150gr at 2400 from his 307 Win 20" and that is attainable with a 30-30 in a 26in barrel. Of what value is a rechambered Marlin? That is up to you to decide.