I did not say it could not be done - I say at what cost? I just did not know how it was done. For normal head spacing with a 30-30, the rim will be against the back of the barrel (chamber mouth). For an extractor to grab it, there would have to be a notch cut into the breech face. If you set the head space by turning the barrel in and out, there is no way of indexing the notch to the extractor and still have proper head space. I guess you could cut a notch all the way around, like described above - sort of a cone type breach face. I was just thinking that if you recessed the rim into the bolt face, the case would have to stick out the end of the barrel a little. To do this I would think you would short chamber the 30-30 so it would stick out a little. Either way you go you are going to have to custom machine the breech face or custom chamber the 30-30. On my Savage model 40 that has a rimmed case, the breech is cone shaped, to accommodate the extractor. The example that you gave for the other site, he used a Hart barrel. I assume that he bought a blank and either threaded, chambered and machined the breech face for his application himself or hired a gunsmith to do it. If you are doing all the work your self, then costs will be way down, but if you have to hire someone to do this, the costs start going up. It is fun to think about a project based on the 30-30; I just do not know how practical it is. You can get a 308 in a Stevens or Savage gun. If you hand load, you can down load it to 30-30 levels. But when you want something that few have, you can justify it by simply saying I want it. Like I mentioned above, it would probably have to be a single shot. Of course I personally prefer single shots over a magazine feed bolt and would feel this as no handicap. One other thought for the bolt face, why couldn't you just machine the the whole face flat and put a spring clip on as an extractor? The head space is off the bolt face.