After contemplating it for quite awhile, I decide to go ahead with my plans to chop down my 16" Bushmaster Patrolman's Carbine to 14.5" and add a permanently attached extended flash hider.
All of the work was done by me, in the machine shop at work. Once the barrel was removed from the upper receiver and transported to the shop, it stayed there, separated from the lower receiver at home until it was finished and could be legally reassembled.
All of the following photos are clickable links to larger images. Here is a 'before' photo of the barrel in it's stock 16" configuration. Sorry if it's a little blurry, it's a crop from a larger image:
And here's the barrel after going "under the knife" to be cut, threaded, and crowned to 14.5":
This is the Sabre Defence Industries extended A2 flash hider, compared to a standard A2. With this FH pinned and welded per ATF specs, the barrel is a legal 16.1":
And here is the end result:
With the barrel in its new configuration, it now accepts an M7 bayonet:
It was close, but all barrel markings are still intact:
And most importantly, my assistant appears to be comfortable with the results: