This is a cross post from the Samson Industry page just to see if maybe you guys know anything. This has happened with one Samson and one Rainier Arms branded handguard on two different barrel nuts. Pictures are of the Samson, but the Rainier does the exact same thing.
I purchased the 15'' Evo keymod from Brownells (and one from Ranier) last week to use on my 6.5 Grendel build. Everything was going very smooth - though once I took some pictures of the rifle I noticed my barrel was nowhere close to being centered in the handguard. I was able to move it by hand and center it - so I decided to tighten the clamping bolts some more. All seemed well. This morning I get to the range and the handguard seems to be moving just from supporting the rifle on the rest. After a couple shots it looked like this -
I believe that I've tightened the bolts enough - as the ears are fully engaging each other as shown...
The barrel nut is standard mil spec and the thermal bushings fit exactly as they have on all my other builds. I know the barrel nut is not loose because I am getting fantastic accuracy out of the rifle.
Any advice on what to do?