Dye Single Trigger Grip Screws

[fstop_22]

My friend acquired this Dye chrome single trigger frame as part of a trade and since he already had one just like it he passed it along to me. Unfortunately it did not come with grip screws. In the past I've found that most grip screws have been fairly universal or at least easy enough to pick up at a hardware store. This size screw is larger than what I typically see in a grip frame and I can't seem to find a screw that fits. An 8-32 is too small and a 10-32 is too big. A metric 4 is too small and a metric 5 is too big. I spent about 30min at the local hardware store trying various thread sizes (coarse to fine, etc) to fit at no avail. The guy at the local pro-shop said he used to see them back in the day and searched his parts but came up empty. Any one know what size this screw might be or have spares? Any help would be appreciated.