This isn't a response to the above, but my membership level disallows me to post directly. I'm not aware of another way to address this group without starting another thread that may not be noticed.
I've been watching from the sidelines, intensely interested in rimfire precision but heretofore unable to play for various reasons. I bought a Terry Cross stock from Paul Parrott in 2019, talked with him about a build mimicking Mr. Cross's Sentinel S.W.S. rifle and using his bottom metal. I was poised to jump into the Vudoo pool when the pandemic and other stuff hit. Now, I'm thinking about reentering and having built what's likely to be the last rifle of my life.
Aside from the entertaining Peyton Place aspects of the thread, the mechanical design discussion has been fascinating. I'm a retired physician, so numbers don't scare me, but Mr. Bush's and others' detailed analyses are fascinating. You're covering things I've never needed to think about before--never knew such questions occur.
So...let me drop an ignoramus's thought here: I like shooting a lot. As Jeff Cooper said, trenchantly, "the purpose of shooting is hitting." That's why all this business is going on: Folks here want to hit targets that are, for their ballistical milieu, tiny and far away. That's what I want to do. What I don't want to do, and what I'm not equipped to do by situation and by inclination, is to fiddle with my rifle. Yes, of course, I clean my guns. Yes, of course, I've learned to disassemble them to a reasonable extent and do kitchen table parts exchanges. But at the bottom line, I want to set it and forget it.
What I want from an M5/M5x, is a finished package. I'm willing and happy to pay for lot testing, because unless one includes a barrel tuner in their setup (thus tuning rifle to whatever ammunition they can get into the magazine), that's the only way to find what'll work. But I don't want to jigger with the magazine catch, the follower, or anything else. Within the limits Mr. Bush sets for workable ammunition, I want everything to go, first pop out of the shipping box. I want nothing to be adjustable, because with this action mated to an approved barrel with an approved chamber and approved bottom metal, the magazines, the mag latch, nothing should need tuning. Mr. Bush hasn't said that outright, but clearly that what he thinks is proper product and production design.
Maybe I'm being impertinent. Maybe I'm butting in where I don't belong. But maybe what I said ought to be said.
Anyway, thanks for your time.