Just saw a 9mm SBR set-up and am rather intrigued.  I've standardized to 9mm for my pistols for now and am attempting to rationalize that a 9mm set-up for my AR would be neat.  With my .223 AR, I shoot rabbits and I think the 9mm would be just as effective given the usual ranges.  Right?  

First, what in the world do I need in order to swap back and forth between .223 and 9mm?  Upper?  Mags?  How about the mag well?  What brands of gear should I check out and/or avoid?!  

Will the sunsetting AWB effect the SBR prices / taxes and availability?  

Thanks!  

9mm FAQ

Basically, you need a 9mm upper, 9mm bolt, mag well block, 9mm (or DPMS hammer), and some Colt, or UZI mags.

Hope that helps,
Jake

ETA the AWB sunset will have nothing to do with SBRs. You'll still have to pay the $200 tax stamp if you want it short.  The only thing the AWB sunset might affect is the availability of 9mm magazines.

Jake...

The DPMS hammer will work in both 5.56 and 9mm ARs?  Have you tried this before?  I would love to have one hammer work with both 5.56 and 9mm - not having to switch hammers would be nice!

Spooky

I have not tried it, but apparently as long as the hammer doesn't have a notch in the front face (DPMS style) it will work in a 9mm setup. I think some people have complained of trigger slap using the DPMS hammer, though. I have a DPMS hammer that I can try with.

On the other hand, I have also read of people using 9mm hammers successfully in .223 uppers.

Jake