Lop it off and recrown the barrel!
Otherwise, just follow Josh's suggestion and swap the unit for the non-vented one.
They are held in place with a nyloc type insert on the barrel threads. No setscrews on the Browning setup.
If you don't have a copy with your rifle, search on Browning's site for the manual for the BOSS system. http://www.browning.com/customerserv...uals/index.asp
They are available (order a BOSS CR instead of the original BOSS). Get the one that matches your caliber.