Yes, all of our scopes are rated for heavy recoil up to 50BMG.
These are commonly used on those platforms.
The ATACR will have a larger body tube (34mm) and ED glass throughout the entire optic where as the NX8 is a 30mm body tube and has ED glass in just key components. There are several reviews on YouTube that may help you in your comparison.
There is currently not a NX8 1-8 with capped turrets available to the civilian market.
Yes. All of our reticles are etched.
There may be other compatible ARD's on the market, but we recommend the Tenebraex TRJMFO-ARD.
8.7 inches
While it will of course be noticeable it will not be as substantial as you might think. We don't publish numbers or percentages as these measurements are not standardized across the industry, but the low light performance is excellent in my own experience.
On the left side of the product page under the product images there is a document file for the NightForce NX8 1-8x24mm Rifle Scope. If you click on the manual and go to page 8 it will explain the diopter adjustment in more detail and how to use it.
Nightforce does not offer an ARD for this scope, but they do offer some flip caps under MPN: A538 and MPN: A539. Below are the links to the pages containing those part numbers:
https://www.opticsplanet.com/nightforce-riflescope-objective-flip-up-lens-caps.html
https://www.opticsplanet.com/nightforce-riflescope-eyepiece-flip-up-lens-cap.html