10.5" HK MR556 upper with AAC flash hider. Low round count, used with normal wear around the shell deflector and charging handle but in very good shape. Has a ported 416 gas block (will run 100% suppressed or you will need to mess with buffers and springs for it to cycle with out a can, or weld the port shut and it will run fine either way) flash hider was once pinned. $1800 shipped or trade for leupold mk6 1-6 cmr plus cash or low end, kiss fsp 10.5" upper plus cash. Please use email.
20150801_191829_resized by T B, on Flickr
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Just an idea of the potential
20150620_185316-01 by T B, on Flickr
20150620_183014-01 by T B, on Flickr