Plugging screw holes

[aitch]

I have a Martini cadet with two mounting holes on the left side of the receiver where a receiver peep sight was mounted. Actually there is a bar affixed to the receiver by these two screws. I plan to fill these holes and am needing a couple of screws to accomplish this with.
I want oval head screws so I can chamfer the mouth of the holes to accept the bevel at the base of the oval head screws. I plan to anneal the screws and then peen them in place after adjusting the length and tightening. Then file and dress them down to a flush condition.
My quandry is that I don't have the sacrificial screws and am unsure of the thread.
It is a number 6 but I don't know if it is 6-40 or 6-48, I suspect the latter.
I have some scope base screws that mate with the thread but have wrong head configuration.
If someone can confirm the thread pitch for scope base screws or suggest where I might get a couple of correct oval head screws, it will be a big help.
Thank you,
Aitch

 

[rayo9954]

This might help.

BROWNELLS : PLUG SCREW KIT - World's Largest Supplier of Firearm Accessories, Gun Parts and Gunsmithing Tools - BROWNELLS

 

[aitch]

This might help.

BROWNELLS : PLUG SCREW KIT - World's Largest Supplier of Firearm Accessories, Gun Parts and Gunsmithing Tools - BROWNELLS

Thanks, but I prefer not to buy a kit, and want oval head so I have some metal to work with.
Also uncertain if thread is 6-40 or 48.

Thanks again for your suggestion.

Aitch

 

[aitch]

If no one has any screws, can someone confirm the thread for me. It's 6-40 or 48 and the thread is the same as scope base threading in a Ruger #3.

Thanks,

Aitch