I posted this in a different forum, but got very little input, so I'm trying here Hey
Thanks for all those that chimed, or are chiming in. I'm a total n00b when it comes to AR stuff, so all help is appreciated.
Want cost effective? Just replace your A2 upper with a flattop using your existing barrel. Then sell the A2 upper on the EE and recoup most (if not all) the costs.
Lots of options when building a 'tack driver'. Personally I'd get an Oly SUM or DPMS upper before going to J&T.
Oh yes you can use the charging handle and bolt carrier for a new upper. Generally you don't want to be swapping bolts back and forth as it increases wear and you could get into an excessive headspace issue after a while. Best bet is to buy a new bolt for the new upper assembly.
However if you just get a new upper receiver (keeping the old barrel) then you wouldn't need a new bolt eh?