Got my 20' madbull disipator barrel on my 416. It has 2 gasblock/front sight connecting points so that my 416 gasblock can be in the right place.
EDIT: fixed the pics.(sonuva whore!!!! I deleted them, re-sized and re-uploaded them and they're still f*cking huge... I give up. their massive and they'll stay massive...)
EDIT 2: Finally got the buggers to work!