I followed the instructions, at least I thought, when I did my YHM Free float quad rail.  Tonight while taking a punch and knocking out the trigger guard roll pin I picked up the rifle grabbing it by the locking ring (of the railed handguard) and it was loose.

The rail must've loosened up while at the range, I can't see the vibration from hammering a pin on the lower breaking it loose.  The rail wasn't going anywhere because of the set screws but it was loose on the upper.  I turned the locking ring tight by hand then took a brass punch and started tapping it tighter by the 4 notches.  The brass punch actually peened one of the ring notches  so I took a flatblade screw driver and tapped it tight

Should I loosen it back up and blue lock tight the locking ring?  

The instructions only said to blue lock tight the set screws.

I assume this is one of their std ffs? Not lw or diamond?
I had this exact same problem.  That is why their newer handguards have the anti rotation screws. I'm not a fan of lock tight, so I ended up buying a new lw ff.  Probably cheaper options but oh well.

I lock tight anything with a thread.

Hrm, it's the standard railed but it does have the anti-rotation screws.  They kept it from moving more than a 1mm or 2mm  but I hadn't realized the locking ring wasn't tight.  




I might loosen the ring and put some blue loc-tite back on there...  It was my intention to have this be solid.  I checked for the YHM tool to tighten this locking ring and no one has one.  I guess flat blade screw driver is good enough?  

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I might loosen the ring and put some blue loc-tite back on there...  It was my intention to have this be solid.  I checked for the YHM tool to tighten this locking ring and no one has one.  I guess flat blade screw driver is good enough?  

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I JUST picked one up from brightflashlights dot com, along with a YHM FF... great guys.

That's where I got mine too, couldn't pass up that deal.