.... Anybody have any thoughts on my idea to use the AR10 platform rather then a bolt action . Really I'm looking at the LMT mws or armalite AR10 for this idea of one rifle multiple calibers in the same parent case family . Looking to have one rifle with 3 barrels . 243 , 308 , 338 . I was looking at the cost to do what I've been talking about . WoW very spendy . I could buy three different rifles for less then doing the whole barrel switch-a-roo thing . I'm really liking the semi auto thing though .
You somewhat answered that question. If you want different caliber capabilty, there are other options. The Savage rifles are pretty simple to change barrels on, and other makes can be adapted to the principle fairly easily also. Barrels, especially take-offs, cost far less than spare guns and uppers, (or AR 10 barrels).
For the money you'd spend on the AR-10, you could buy a very nice rifle, good glass, and a lot of ammo/reloading components, and not have to worry about ammo availability much.
I'm in the "use something common" camp. If ammo truly gets hard to get, trading from someone else is likely. More people have the common calibers, and many may even have unused ammo around in common calibers that they dont have guns for. Reloading is simpler also. Components are simpler in common sizes. Parts can even be broken down from loaded rounds that dont fit your gun.