Do yourself a favor and just eliminate the brass nocks altogether. Use serving thread to tie on on instead. In a pinch you can use dental floss.
There are couple benefits to NOT using brass nocksets. One---it eliminates any wear on the arrow nocks and Two---it increases the speed of the bow a few fps.
I did some experimenting several years ago and found that each brass nockset on the center serving reduces the speed by about 4 fps. Funny thing is I've seen some guys use them to hold a peep in place. Then one over the nock and one under and one below that to hold a release in place while on stand. That has to be nearly 20 fps they've just robbed from their bow.
Oh yeah, there's a third benefit of using serving material to tie one on. It fits all strings.
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