They seem to last just fine.
![Wink ;)](https://czfirearms.us/Smileys/default/wink.gif)
![](http://i16.photobucket.com/albums/b13/armoredman/vz58andADCO.jpg)
That was when I started modifying my rifle, back in...'08? I think? I took it off once to try a MagPul AFG, but it went back on, and the AFG went on the 5.56mm version, instead. It seems to work quite well, with no issues with looseness, etc.
![Cool 8)](https://czfirearms.us/Smileys/default/cool.gif)