Re: New Gen 4 IOR Scope ruggedness
On the subject of the 3-18 x 42s, I have three of them. 2 were purchased very early and are Gen 1s and one that I purchased later is a Gen 2.
One of the Gen 1s broke on its very first outing after 20-something shots on my new AR10. IOR had a Gen 3 replacement in my hands in less than a week and it has been going strong ever since. Both IOR and Scott @ Liberty has said with the Gen 1-2-3 versions it seems they either break almost immediately after being put into service or they hold up. I haven't had any problems with my other Gen 1 or the Gen 2-- they just keep on working.
I also have a 3.5-18 x 50 (equivalent to Gen 4 internals) which has been perfect and I really prefer it to the 3-18 x 42. I like the 3-18 x 42 but the tube/turret configuration with the short rear section usually means when on a bolt gun even mounted all the way back you still have to stretch your neck to get in the eyebox as you physically can't mount the scope far enough rearward. The longer rear tube on the 3.5-18 x 50 and more forgiving eyebox on higher magnification than the 42mm version gives much more mounting flexibility when mounting it on a typical bolt gun and it isn't a problem to achieve good eye relief.
The 42mm version does work great on something with ample rail length and mounting flexibility like an AR. Both the 42mm and 50mm have great reticles, very good glass, the knobs feel quite good and the elevation knob is quite easy to read because of the large diameter and large & widely spaced hash marks.
If I needed any new scopes right now I wouldn't hesitate to buy the new Gen 4 3-18 x 42 or better yet the 3.5-18 x 50; other than the issue with my one known to be problematic Gen 1 I've had very good experiences with all the others.