I am putting together a 300BLK. I have a Vltor MUR and a DD Lite Rail in 14" (the longest they make).
Since I’ve never used a DD Lite Rail, the instructions say to torque the barrel nut to 50 ft/lbs. Easy enough. But what I don’t get from the instructions is whether with the back plate in place and bolted down - can the barrel nut rotate loose once fully assembled?
Or does the DD Lite Rail have another locking mechanism to prevent the DD barrel nut from working loose?
The reason I’m concerned is that even though you torque it down to the spec, without a physical locking mechanism - it could work loose over time and it would be a major PITA to have that happen.
The advantage I see with some other rail systems is that they use the gas tube (or factory barrel nut) to prevent rotation.
Need some input here. Thanks.
Note: I can still return/exchange this rail for either a KAC URX 3.1 or Larue. But both would be only 12" max length.
As you know, the rail attachment collar rotates freely around the barrel nut even after the barrel nut is torqued down. Once you install the rail however, the 6 hex bolts pull that collar tight against the nut and prevent it from rotating, essentially locking the rail and collar against the nut. I’ve seen people question the possibility of loosening, allowing the rail to rotate, but I have a DD Lite 9.0 on an SBR with about 8000 rounds through it and it has just never been a problem. It has remained absolutely solid.
I had pretty much the same configuration on a previous build (14" D&D, UBR, Vltor MUR, etc) on a noveske gen II lower and while it was a fantastic rifle it was an absolute pig, even with a LW D&D barrel.
Awesome to look at, just sucked to hump around. Figured I’d give you a heads up lol
Don’t worry about rotation with the Lite Rail. Once installed, it ain’t going to happen (as others here have mentioned).
I had a similar gun in 556 with a Denny’s Tactical model WOA 556 (non LW) barrel, 14" LR, and UBR. It was heavy. After a 1 day class I was in with it, I turned it into a RECCE type gun and built a lighter weight rifle
