You follow the simple liner rebuild instructions until you have the constrictor installed and well centered. Then you simply place the selected O-ring on top of the installed constrictor as an extra, added step. The O-ring selected should be larger than the maximum diameter of the erection at the base as these O-rings will not stretch in any significant amount. It is not there to constrict, it is there to reinforce the entrance and shape it. When you consider that the liner will be "wrapped around" the O-ring making its I.D. even smaller, a 325 size is probably about the smallest you would want to use here..

Then the liner is simply installed on top. You just pull the liner down over the o-ring as though it were not there. It is really quite easy. This traps and holds the O-ring in place after the liner is stretched down and over the entrance end of the receiver. The O-ring shown is a bit smaller than the diameter of the 2-inch tubular housing. I also use a bit larger size which fits right to the edge of the receiver diameter. Once the liner is installed on the entrance end, you finish up the rebuild normally. The effect on the finished receiver is quite obvious. Even with considerable tension, the O-ring working with the face of the constrictor prevents the formation of the funnel shape.

12/03