We've tooled up our own custom M5 screws specifically made for mounting ski bindings to swap plates or inserts. The head is tapered and fits like a flathead screw, but with a smaller diameter head so that they fit bindings which require a smaller diameter clearance. The underside of the head has locking serrations to help ensure that the screw doesn't back out over time. High quality stainless steel. For use with a Pozi #3 phillips head screwdriver.
It is very important to maximize the number of threads engaged in an insert or a swap plate, so be sure to measure carefully. Inserts can accommodate from 3mm min to 6mm max of thread engagement. We like to target 4mm of thread engagement. Do not exceed the min/max numbers for any reason - you will not get a secure mount. These screws fit exactly like allen head flatheads in terms of length.
Binding Freedom have some Screw Lengths for popular binding configurations here so check these out and see if your lengths are here.