I want to thank you folks for helping me out, I really appreciate it.
I am retired and 71 years old. My wife and I are just barely over the, being comfortable, line when it comes to finances. That being said most our money is spoken for when it comes to current and future expenses.
I get 500 a month for my food and other incidental personal expenses. That doesn't go far when it comes to food, lathe bits, end mills, drill bits and a few beers every once in awhile at the local watering hole. I have to save long and hard for every thing I buy.
I currently have a complete 308 and a 80% ar15 lower. I really like the 500 auto max but as was said it is proprietary and expensive. I've looked into other options like buying a complete upper from KAK or even just a bolt or bolt and carrier then piecing all the rest of it together, again expensive and a lot of work and tinkering...just not realistic for me.
I think I'm going to go with the ar15 50 beowulf. I already have the lower receiver. I can mill this, buy a reasonable lower parts kit then a complete upper. I believe God willing by June I can have this thing done. I've found brass and dies and I make my own bullet molds so looks like I'm headed in this direction.
I want to thank you guys for helping me along...I do appreciate all the info, which you can never have enough of.