I read your posts, there was nothing to apologize about. You are a person who is thinking (outside the box) looking for some suggestions on your next build. Oftentimes for me what is going on in my mind, and....what is coming out of the keyboard do not always project what I want the fingers to project. Personally if I do not like what someone has put down in a post, I simply move on to another post, there is no need/room for being judgemental.
My first thoughts are to stay away from the proprietary cartridges, period!! I just ran a search on the 7 SAUM that you wrote about, presently "they are available", and....they are $90 for 50 pieces. But....the operative word is "presently". I refuse to let myself be held hostage by a company who is touting a cartridge to make money. I like what "PAVEMENTENDS" wrote about being "ole school cool", and his recommendation for the 7mm Ackley Improved. I was going to build a .280 Ackley Improved, but realized that Nosler deviated from the original Ackley Improved process of using the parent cartridge and blowing out the case with the 40 degree shoulder, making that cartridge a Nosler proprietary one. So....presently have two rifles that are in .270 Ackley Improved on a 1:10, 26 inch barrel. The rifles shoot 150gr ABLRs between 3100-3300fps and it doesn't take a pound of powder to load 20 rounds of ammunition; powder = weight = recoil. The brass is and probably will always be available, and not at the $4.50-6.00 apiece price range. The .270 AI is one of the most under appreciated, unrecognized and underrated Ackley Improved cartridges that are out there. If you want to really hurl high BC cartridges that are light on the shoulder, do not cost a small fortune for components and use a pound of powder to load 20 rounds you might want to take a look at this cartridge, only build the rifle with a 1:8 barrel. The .270AIs that I have will shoot two shot, one-inch groups at 300 yards with the 150 ABLRs. After the second round, the third round then group will open up because the barrels are light contoured hunting barrels. If you really are interested in the cartridge, try PM FEENIX on this site, he is the one who introduced me to this cartridge. He is a great guy and extremely knowledgeable with this cartridge. I am surprised that he hasn't jumped in here. I know he has rifles that are built with fast twist barrels and hurling the heavy BC bullets. Good luck with your build, they always are fun to put together.