Hi, Last year I installed an after market Tensei Blue AV Series (SFW) on my G425.  Because I cut it 1 inch shorter than standard, I installed a tip weight to bring the swing weight to D4.  Saturday I heard something rattling inside the shaft.  Initially I suspected the tip weight broke off but after removing the grip, a small black metal pin approximately 1/2 long fell out.  Any idea what this pin is?  Thanks.