AIAX Rail Attachment Screw Question

[MTAR15]

I'm making an attachment on the bottom of my AIAX out of PTFE that will allow me to use the rifle for 1000 yard bench rest shooting this season.

I have 2 questions about the screws that are used to attach the rails to the key mod forend.

1. What threads are these screws, I know they are metric and left handed. But what size and pitch are they?
2. Any idea if and where I can buy these screws?

Thanks for any help.