almost an inch of bearing, with both bolt-up rings (one welded to the rail, the other behind the nut, bolted together), though. also, the port cover rod captures the boltup ring, further impairing movement.
from my own experience beating the absolute dog-shit out of my guns and breaking a lot of components, you're gonna break or bend it before it loosens up- which i've done.
i cant speak for the RIS, never used one.. have one on the way, though.. i have high expectations
the Troys dont get a lot of use, and i couldn't tell you why. i've handled a few, including operating one.. they're heavier- and i'm sure that's a big part of it.. they're also pretty sharp- not nearly as much finish machining. i do know that companies like Larue and DD would sell a lot more rails if they lowered their prices to Troy/YHM/MI level- but they cannot, and still make money, because of how much effort goes into their rails. that doesn't directly correlate to superior durability, but it's certainly evidence of it.
you can get or not get any rail you want, and for any reason you want- but the risk of rotation with a DD Lite is just not there

