I am a nervous wreck today waiting to close the deal on receiver #1. I will never grow up. There is this wonderful material available to us machinists these days called AISI half hard 4140 Chrome Moly. At Rockwell 38 Hardness it machines slowly but beautifully and you can make a modern bolt action receiver out of it as is. The old timers would have killed for it. In the shop where I am employed we stock it as Accraloy, so there are plenty of low cost scraps available. A monoblock and locking bolt made from this material, coupled with modern steel tubes, is the ticket for this moderately excessive pressure project. Sorry but no to the extractors. Always reload your hunting ammo in well used cases you can afford to lose cause when you crack the gun open with game down you don't want to see anything but smoking holes.