Need help!  Is the standard A2 sight post from a 20" barrel interchangeable with an M4 sight post with a 14.5" barrel?

Thanks

No such thing as an "M4" sight post.

USGI front sights are either A1 (5 slots) or A2 (4 slots).  Either will fit a standard front sight assembly.

There is a difference in the height of the front sight BASES between the M16A2 & M4.

However most manufacturers use 1 height.  So unless the M4 barrel is from Colt, its not an issue.

This discussion is pretty academic 'cuz the M16 and M4 front sight tower is [i]part of the barrel[/i], just like the barrel extension and fitted at the factory.  There's no military part number for the sight tower.  There is no way to remove and replace the sight tower without special skills, tools, and parts.  A good way to bugger your rifle is dick with the front sight tower.  When done to true match rifles the tower is often secured by Allen screws rather than pins.

-- Chuck

A friend of mine bought a Colt M4 14.5" barrel without a sight tower.  He wants to keep his rifle all Colt, but he was not sure if he could just put on a sight tower from a 20" A2 barrel.  Looks like he may have to order one from Colt.