Hey Juice, You aren't crazy. I'm thinking the same for my 6.5 Whatzit conversion kit. I have an AR with four uppers and it is handy as hell being able to make the three minute caliber swap. Keep us all posted o.k.?
I'm thinking of a complete upper, in say 7.62 x 39 ready to rock and roll after pushing one catch, and popping one pin!
Not sure what the big deal is about having a complete upper, I have seperate optics for 5.56 and 6.8 and both attach to the receiver via LaRue mounts. The 2 calibers shoot so close I really don't even need to swap optics for work out to 300 yards.There's really no advantage in buying another upper. You're not going to carry it around with you. Yes, it's faster to install. I'd be even faster if you just bought another complete weapon in 7.62x39mm.
Many customers who've bought 5.56 rifles have ordered complete rifles in 6.8 so they can keep the optics zeroed for each caliber. This argument would apply for separate uppers also.
We hope to begin making sights for the gas block. Those sights would allow each barrel to be zeroed for windage and elevation. Then one could simply change barrels and the rifle would already be sighted in.
On the other hand, we have designed the upper receiver so that it's relatively inexpensive so another upper is not such a bad idea.
Alex J. Robinson
Robinson Armament Co.