I got my new M4-LEP II upper from CMMG in March. First time I shot it I noticed something was loose other than a little wiggle from the upper and lower.
I realized that the CMMG K7 quad rail was moving. I was able to hand tighten the nut a bit but that didn't hold. I resorted to tightening the Allen bolt at the bottom for the time being.
Well now that Allen bolt has disappeared and I am getting tired of hand tightening the jam nut.
Is there a tool suitable for tightening that jam nut without marring anything? Everyone is telling me it should have come with a wrench.
I submitted a support form on cmmginc.com last week but haven't heard back.
I believe it's a standard size like Midwest Industries or DPMS. You could also use a strap wrench.
I tried the strap wrench. It got it tighter than any other time I had tried but it still worked itself loose duing my last 3-gun.
Haven't heard a word back from CMMG. I stopped by Black Rifle while I was in Fayette / Columbia, and they didn't have a wrench for it either. They told me to call CMMG, which I guess I had probably do.
The CMMG barn door was open at the last 3-gun... seriously thought about poking my head in and looking for wrench and set screw.
I sent an email this time to the support address and got a prompt reply asking for my address.
In the mail yesterday I had a wrench and set screw.
Handguard is now NICE and TIGHT!'
Rock on CMMG.