2152hq,
First don't confuse me with an expert at this process. This is immersion learning for me; a good deal of it the hard way. The main reason I am posting is for others to learn along with me and see the mistakes as well and I am making plenty of them. I do believe the Winchester 21 action is plenty strong for the job. Winchester itself built a few 405 Winchester rifles on the action. They didn't continue because they couldn't get the accuracy they desired not because of any strength concerns. Also, since I am making the actions as well I am using 4340 steel alloy which has a much higher yield strength and tensile strength than the forged steels that Winchester used in their shotguns. When I harden them they will far exceed any requirements. Winchester 21s were much stronger than Parkers, LC Smiths, or Fox's (I may get some backlash from this statement). Galazan did have some design changes done in anticipation of building large DRs as I understand it;I think in the order of 577.

I really don't have any concerns if I stay about 45,000 psi or below. I would not want to do anything like 60,000 without a lot of true analyses. For example, I would like to build a 6.5X68R but I am concerned with the pressure. Also, since we can modify the internal design by alterning the code I will increase the amount of steel directly behind the striker holes in order to put in bushings and firing pins. That will substantially beef up that potentially weak point. The negative side of that is now having a hammer and firing pin and not a single integral firing pin hammer. The single hammer firing pin is virtually indestructable and can be dry fired as much as you like. Now the firing pin is subject to failure. But it is an acceptable trade-off.

I would really like to talk with David Yale. Would you PM me his contact information? Also, the reason to use the 21 as the basis of the design is my long-time love for the shotgun. It is not the ideal design for a DR but fits my needs since it will pair with the shotgun.

Hope this answers some of your questions.------------Bill