Our own Formidilosus had some things to say about reliable scopes in an older thread. I kept it in my files.
His background was a big factor in listening his comments on what scopes hold up:
"I work at a place that fires a lot of ammo. I see over half a million rounds a year on average get fired. 90% of those rounds are tracked. Weapon zeros are checked nearly daily, scopes, mounts, rifles, ammo, etc, are being tested constantly. If a rifle has even a .5 MOA shift in zero we will see it almost immediately. My thoughts are this- scopes are an aiming device. They are a container to hold my reticle so that I can hit targets. I do not care about scratches, dings, or ring marks. I do care that the bullets go where the crosshairs are pointed. My first requirement is that the rifle stays zeroed through use."
Failures or issues with these scopes are extremely rare-
1). Nightforce NXS/ATACR/BEAST
2). Bushnell LRHS, HDMR/DMR, ERS, XRS
3). SWFA SS 6x, 10x, 1-6x, 3-9x, 5-20x
4). S&B fixed 10x PM
5). Hensoldts
6). Older Leupold fixed power Mark 4's/Ultra's
I want to thank Formidilosus for the above information.
Ross