I have a winchester 140, think same as the 1400, waas wondering my son wants a sling on it . I mounted the stud on the stock and have a stud to go thru the magazine cap. when I took the cap off there is a disk just slightly smaller than the cap an raised just off the bbottom of the cap, is this some type of vent system there is a small hole in the center of the cap maybe 1/64 or less, will it hurt drill the hole out to 1/8 in or so to put the stud in? don't want to hurt function now or in future, caps are hard to come by and didn't want to ruin this one, sling is now thru the vent rib I know it is going to rub blue off if leave it there.