The good people at Alliance Armament have developed a 5.56 caliber upper receiver for the MAC 10 submachine gun. MACs are the most affordable fully automatic firearms you can find in the USA, so this is great news! The Following was taken from Alliance’s announcement on Uzi Talk:

“Alliance has just received full ATF approval for their SABRE upper!

5.56×45 on a MAC and accepts all AR mags including BETA-C types.

Initial run is for M10’s but M11’s and M11A1’s are in the works and should be close behind.

Alliance is currently adding all the details to their website and there’ll be a list for anyone interested in getting one.”