I was reading the 1911 clinic thread at the top of this page ,And see VIS mentioned in some of the posts about the barrel link. I want to know what that abbreviation stands for.
VIS = Vertical Impact Surface
It refers to the vertical surface in the frame which the recoiling barrel cam lugs contact and stop against after link-down.
The barrels rearward travel needs to be stopped by the VIS, and not by slamming down into the frame bed before it contacts the VIS.