MSH....on the 6x45, don't know about it, but the 6x35, Knights Armament went with it in the PDW,,,,it looks sweet, but civilians can't get it with out a permit...
www.knightarmco.com/images/pdw1.html
I have read about the 6.8 SPC, unless you want to reload your self I would have to agree that it is a dead horse...It was designed as a alternative to the 7.62x51, it packs a punch but at close to medium range but at a distance,,,,,not so good. The 6.5 Grendel would be much better, it has a much better BC for distance with pretty much the same punch.....all these have be the alternative to the AR-10 just because of the over-penetration at close ranges....but I said in my article, even a 9mm will over penetrate at the right range...
On the alternatives......the 6.5 Grendel uses a AR-15 lower, were as the 6.5 Creedmore uses a AR-10 lower..but all in all ammo is not an easy thing to come by depending where you are.....the 7.62-.308 can be found about anywhere....well if they have it in stock..LOL
As for The Mags.........yes it is true....for now...lets hope that Westrom and Magpul can work something out and we can get the P-Mags for the AR-10.
On the Large cap mags..........nope....not sure you would be able to wield it if they had one....50 or even better 100 rounds of .308 would be alot of weight. 25 is the biggest I have come across, but I have stayed with the 20s, and I like to use the 10s for target shooting, need to get another, anyone have a spare 10 round Gen 2 they want to sell....???
On the dear hunting thing...well I say buy the best that you can get if you want the durability that our soldiers and LEOs place their lives on,,,,,and yours if it was to come to that....
On the Irons....go with the MI sights, they are affordable and durable.....