With the right tools its very easy. For removing a barrel assembly, you'll need an action block (I recommend the DPMS Panther Claw) and a barrel nut wrench. I really like the PRI barrel nut wrench, but you have to remove the FSB and flash hider to use it. For removing the FSB, you'll need Brownell's FSB block and a good set of punches. The flash hider is easy, any adjustable wrench will do you fine, just remember to get a new crush washer. All of the tools can be had from Brownell's for around $160
What is it you are wanting to do? Swap out barrel assemblies, barrel only, install a ff handguard...?
Originally Posted by itotorica
How dificult or how expensive is to change barrel?