These are custom made Yugo/Zastava-style grip screws with the big flat head and a lock washer.  These are the standard 6mm thread diameter, 1.0mm pitch and approximately 100mm long -- about 96mm shaft and a 3.5-4mm thick head.  These were used in the military M70, M72, M76, M77, M85 and M92 series weapons.

The screws are black oxide coated stainless alloy that has a hardness of approximately 10.9.  An external tooth silver lockwasher is included.

The gallery has a number of photos that show grips, nuts and additional screws purely for illustration.  The grips shown are original Yugo/Zastava grips so you can see the size comparison.

Note:  The last photo has the new black grip screws by an silverish worn looking screw.  That worn screw is an original Yugo screw from a M70B1 kit so you can see the size comparison.