M4 front sight alan screw

[JonMaximus]

Hi there,

I'm finding trouble finding the right sized alan key for the tiny screw underneith the front M4 sight. I need to tighten it but my alan keys are either too big or too small. Is there a special key or should I keep shopping for key sets??

Thakns

[coach]

are your hex keys metric or SAE? I use metric set since I bought almost all metric for my car.

I believe you are looking for the 2mm or 2.5mm key to remove that grub screw.

I use this:

http://www.canadiantire.ca/AST/brows...ey%252BSet.jsp

if your grub screw is slightly stripped, it could also explain why an SAE set won't work.
1/16" < 2mm
1/8" > 3mm