Mossberg 500 barrel comp and backboring?

[Mattexass]

After seeing the the Vang comp 870's it got me thinking what do they do that is so special? What is so special about backboring and compensation ports that I cannot do myself to my 500? Does anyone have any kind of experience with something like this?

[bladeworks123]

I'm not sure, on a combat or utility defense style weapon why it would be any advantage to back bore the barrel, unless you want a tighter pattern and higher velocities. If you were shooting sporting clays maybe.

The compensator I can see for reducing recoil some.