took in a nice one of these in trade recently, its a 20" gun that is missing the front bead

I went to numericks and ordered the bead they had listed on there diagram
the bead they shipped has larger threads than the barrel will accept.

I don't have anyway of measuring the tread size

does anyone know what the tread rate and count is for a 916, or should I just go ahead and buy the universal kit and put a fiberoptic front bead on it
since it might have been cut down long ago?

$2.50 for a bead, $15 for the universl kit