M4 front sight

[yote]

Hello, am hopeing someone here can help me out the front sight on my M4 has come loose and am unsure what exactly I should use to tighten it I was thinking some pliers but I hate the idea of chewing up the nut...so what should i use?

[Alaskapopo]

I used pliers and they worked ok.

pat

[HDRDKG]

Use a 5.5 mm open wrench.

[yote]

Thanks that work now heres another question what should I use to make sure it doesn't come loose on me again? I ask because am really afraid to loose that front sight speacialy has hard as Benelli parts seem to be to find, so any suggestions?

[Kinny]

Red Loctite.