Just picked up a Scar17s but  the iron sights came in a zip lock bag
so I reinstalled the front and back sight with one small problem:

(On the adjustable front sight )
If you look very closely there is a nut cap on the one side of the sight that, .i guess, prevents the adjustment component from backing out (opposite side of the side that you adjust )

If you look very very closely there are two miniature holes in this nut cap with what appears to be two posts that you screw down to lock the nut cap once is is screwed on

Anyone know what tool would be used that would be small enough for these two posts????


(it looks like a miniature Allen key but I've never seen anything that small and I'm wondering if it's proprietary)

Thanks

There's supposed to be a small roll pin that fits in there.

What the guy above said. Roll pin.

Was this a used rifle or did it come like that new from the factory?  I would hope it's the former...

no it's used (like new condition except for this one issue)

the guy must of just forced it off   (the roll pins are still in the nut cap and the tip of them seem pushed in all around the screw threads) i'm starting to think the threads are stripped as well
He probably forced it off with a screw driver or something

So i tried calling FN to see if they would send me the part but I couldn't get through

http://www.midwestgunworks.com/page/mgwi/ctgy/scar-parts
 

So since its off.  Just hammer the roll pins through.  I broke mine off 4 years ago.  The end of the adjustment screw came off with it.  The screw does not need that cap to keep from coming off.  There is a spring pin that keeps the screw from turning unless you turn it with a tool.  If that screw turned without assist you would need to correct the sights every time you shoot the rifle.  Check to make sure the screw has the extra nub on the end before you worry about putting that cap back on.  You probably need the screw by the way the roll pins are mashed over.

The nut-cap broke off or fell off of one of my SCAR barrel assemblies that I ran pretty hard and I've yet to notice any negative effects after that.  The front sight hasn't fallen apart or anything

Maybe just live without it?