I taper the hole that the pin goes through by driving a 1/16" or 3/32" - depending on the size of the pin - "drift punch" into the hole, spreading out the edge of the hole, after I have pre-shaped the guard to almost final tolerances. Then peen down the extra length of the pin and as you do that the lips of the "crater/hole" that were spread outward, also get mashed back INTO the pin along the rim of the hole. This works very well. But don't grind of f the tapered depth of the crater any more that you have to. You do have to grind off the mushroomed top of the pin, though.
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I hope this helps, off to the AKI, so I wont' be back online until next week. Best of luck!