Does anyone here know what size and thread pitch the front sight screw on a MK II Slab Sided Target Model is? I thought it would be 6-48 but that doesnt appear to be the case...

The reason I ask is the barrel on mine is cut back to 5 inches instead of 6 and 7/8. I want to mount a Volquartsen comp on it, but I need to redrill  front site screw hole.

Also whats the best place online to buy a drill bit and tap as a set?

Thanks in advance.

5-40.I bought 100 stainless socket head cap screws 1/4" long from McMaster Carr for my Mk11 and they worked perfect.Use of 5-40 thread is rare.