Many are drilled out a little to create a dimple, then filled with a paint. The dimple protects the paint from abrasion. (or is supposed to)
Forgot this earlier some makers of tritium sights do a replacement vial program when it dims.
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Allan Quatermain: “Automatic rifles. Who in God's name has automatic rifles”?
Elderly Hunter: “That's dashed unsporting. Probably Belgium.”
